https://bugs.gentoo.org/932579
https://github.com/boostorg/charconv/pull/183
--- a/libs/charconv/test/from_chars_float.cpp
+++ b/libs/charconv/test/from_chars_float.cpp
@@ -440,6 +440,7 @@ void test_issue_37()
         overflow_spot_value("1.0e+9999", HUGE_VAL);
         overflow_spot_value("-1.0e+9999", -HUGE_VAL);
     }
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     else
     {
         overflow_spot_value("1e99999", HUGE_VALL);
@@ -447,6 +448,7 @@ void test_issue_37()
         overflow_spot_value("1.0e+99999", HUGE_VALL);
         overflow_spot_value("-1.0e+99999", -HUGE_VALL);
     }
+    #endif
 
     overflow_spot_value("1e-99999", static_cast<T>(0.0L));
     overflow_spot_value("-1.0e-99999", static_cast<T>(-0.0L));
@@ -530,20 +532,22 @@ int main()
     odd_strings_test<float>();
     odd_strings_test<double>();
 
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     simple_integer_test<long double>();
     simple_hex_integer_test<long double>();
     simple_scientific_test<long double>();
     simple_hex_scientific_test<long double>();
+    zero_test<long double>();
+    test_issue_37<long double>();
+    #endif
 
     zero_test<float>();
     zero_test<double>();
-    zero_test<long double>();
 
     boost_json_test<double>();
 
     test_issue_37<float>();
     test_issue_37<double>();
-    test_issue_37<long double>();
 
     test_issue_45<double>(static_cast<double>(-4109895455460520.5), "-4109895455460520.513430", 19);
     test_issue_45<double>(1.035695536657502e-308, "1.0356955366575023e-3087", 23);
@@ -1846,40 +1850,29 @@ int main()
         spot_check_nan<float>("-nan", fmt);
         spot_check_nan<double>("nan", fmt);
         spot_check_nan<double>("-nan", fmt);
-        spot_check_nan<long double>("nan", fmt);
-        spot_check_nan<long double>("-nan", fmt);
 
         spot_check_inf<float>("inf", fmt);
         spot_check_inf<float>("-inf", fmt);
         spot_check_inf<double>("inf", fmt);
         spot_check_inf<double>("-inf", fmt);
-        spot_check_inf<long double>("inf", fmt);
-        spot_check_inf<long double>("-inf", fmt);
 
         spot_check_nan<float>("NAN", fmt);
         spot_check_nan<float>("-NAN", fmt);
         spot_check_nan<double>("NAN", fmt);
         spot_check_nan<double>("-NAN", fmt);
-        spot_check_nan<long double>("NAN", fmt);
-        spot_check_nan<long double>("-NAN", fmt);
 
         spot_check_inf<float>("INF", fmt);
         spot_check_inf<float>("-INF", fmt);
         spot_check_inf<double>("INF", fmt);
         spot_check_inf<double>("-INF", fmt);
-        spot_check_inf<long double>("INF", fmt);
-        spot_check_inf<long double>("-INF", fmt);
 
         spot_check_nan<float>("nan(snan)", fmt);
         spot_check_nan<float>("-nan(snan)", fmt);
         spot_check_nan<double>("nan(snan)", fmt);
         spot_check_nan<double>("-nan(snan)", fmt);
-        spot_check_nan<long double>("nan(snan)", fmt);
-        spot_check_nan<long double>("-nan(snan)", fmt);
 
         spot_check_nan<float>("-nan(ind)", fmt);
         spot_check_nan<double>("-nan(ind)", fmt);
-        spot_check_nan<long double>("-nan(ind)", fmt);
 
         spot_check_invalid_argument<float>("na7", fmt);
         spot_check_invalid_argument<float>("na", fmt);
@@ -1889,8 +1882,22 @@ int main()
         spot_check_invalid_argument<float>("  1.23", fmt);
         spot_check_invalid_argument<double>(" 1.23", fmt);
         spot_check_invalid_argument<double>("  1.23", fmt);
+
+        #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
+        spot_check_nan<long double>("nan", fmt);
+        spot_check_nan<long double>("-nan", fmt);
+        spot_check_inf<long double>("inf", fmt);
+        spot_check_inf<long double>("-inf", fmt);
+        spot_check_nan<long double>("NAN", fmt);
+        spot_check_nan<long double>("-NAN", fmt);
+        spot_check_inf<long double>("INF", fmt);
+        spot_check_inf<long double>("-INF", fmt);
+        spot_check_nan<long double>("nan(snan)", fmt);
+        spot_check_nan<long double>("-nan(snan)", fmt);
+        spot_check_nan<long double>("-nan(ind)", fmt);
         spot_check_invalid_argument<long double>(" 1.23", fmt);
         spot_check_invalid_argument<long double>("  1.23", fmt);
+        #endif
     }
 
     return boost::report_errors();
--- a/libs/charconv/test/from_chars_string_view.cpp
+++ b/libs/charconv/test/from_chars_string_view.cpp
@@ -116,17 +116,23 @@ int main()
 
     test_float<float>();
     test_float<double>();
-    test_float<long double>();
 
     test_float<float, std::string>();
     test_float<double, std::string>();
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
+    test_float<long double>();
     test_float<long double, std::string>();
+    #endif
 
     #if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
 
     test_float<float, std::string_view>();
     test_float<double, std::string_view>();
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test_float<long double, std::string_view>();
+    #endif
 
     #endif
 
--- a/libs/charconv/test/github_issue_110.cpp
+++ b/libs/charconv/test/github_issue_110.cpp
@@ -42,7 +42,10 @@ int main()
 {
     test<float>();
     test<double>();
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test<long double>();
+    #endif
 
     #ifdef BOOST_CHARCONV_HAS_FLOAT128
     test<__float128>();
--- a/libs/charconv/test/github_issue_122.cpp
+++ b/libs/charconv/test/github_issue_122.cpp
@@ -52,7 +52,10 @@ int main()
 {
     test<float>();
     test<double>();
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test<long double>();
+    #endif
 
     return boost::report_errors();
 }
--- a/libs/charconv/test/github_issue_152.cpp
+++ b/libs/charconv/test/github_issue_152.cpp
@@ -188,7 +188,6 @@ int main()
 {
     test_non_finite<float>();
     test_non_finite<double>();
-    test_non_finite<long double>();
     #ifdef BOOST_CHARCONV_HAS_FLOAT16
     test_non_finite<std::float16_t>();
     #endif
@@ -204,7 +203,6 @@ int main()
 
     test_non_finite_fixed_precision<float>();
     test_non_finite_fixed_precision<double>();
-    test_non_finite_fixed_precision<long double>();
     #ifdef BOOST_CHARCONV_HAS_FLOAT16
     test_non_finite_fixed_precision<std::float16_t>();
     #endif
@@ -220,7 +218,6 @@ int main()
 
     test_min_buffer_size<float>();
     test_min_buffer_size<double>();
-    test_min_buffer_size<long double>();
     #ifdef BOOST_CHARCONV_HAS_FLOAT32
     test_min_buffer_size<std::float32_t>();
     #endif
@@ -232,5 +229,11 @@ int main()
     test_failed_values();
     #endif
 
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
+    test_non_finite<long double>();
+    test_non_finite_fixed_precision<long double>();
+    test_min_buffer_size<long double>();
+    #endif
+
     return boost::report_errors();
 }
--- a/libs/charconv/test/github_issue_158.cpp
+++ b/libs/charconv/test/github_issue_158.cpp
@@ -93,6 +93,7 @@ void test_values_with_negative_exp()
     BOOST_TEST_CSTR_EQ(buffer, "0.00000000000000000000099999999999999990753745222790");
 }
 
+#ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
 void test_long_double_with_negative_exp()
 {
     char buffer[256];
@@ -126,6 +127,7 @@ void test_long_double_with_negative_exp()
     // BOOST_TEST_CSTR_EQ(buffer, "0.00000000000000000999999999999999999997135886174218");
     BOOST_TEST_CSTR_EQ(buffer, "0.00000000000000001000000000000000000000000000000000");
 }
+#endif
 
 void test_values_with_positive_exp()
 {
@@ -407,6 +409,7 @@ void test_zero()
     BOOST_TEST_CSTR_EQ(buffer, "0");
 }
 
+#ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
 void test_long_double_with_positive_exp()
 {
     char buffer[256];
@@ -438,6 +441,7 @@ void test_long_double_with_positive_exp()
     BOOST_TEST(res);
     BOOST_TEST_CSTR_EQ(buffer, "100000000000000000.00000000000000000000000000000000000000000000000000");
 }
+#endif
 
 template <typename T>
 void test_spot_value(T value, int precision, const char* result, boost::charconv::chars_format fmt = boost::charconv::chars_format::fixed)
--- a/libs/charconv/test/limits.cpp
+++ b/libs/charconv/test/limits.cpp
@@ -227,7 +227,10 @@ int main()
 
     test_floating_point<float>();
     test_floating_point<double>();
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test_floating_point<long double>();
+    #endif
 
 #ifdef BOOST_CHARCONV_HAS_INT128
 
--- a/libs/charconv/test/limits_link_1.cpp
+++ b/libs/charconv/test/limits_link_1.cpp
@@ -3,6 +3,7 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/charconv/limits.hpp>
+#include <boost/charconv/detail/bit_layouts.hpp>
 
 void test_odr_use( int const* );
 
@@ -28,7 +29,9 @@ void f1()
 
     test<float>();
     test<double>();
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test<long double>();
+    #endif
 
 #ifdef BOOST_CHARCONV_HAS_INT128
 
--- a/libs/charconv/test/limits_link_2.cpp
+++ b/libs/charconv/test/limits_link_2.cpp
@@ -3,6 +3,7 @@
 // https://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/charconv/limits.hpp>
+#include <boost/charconv/detail/bit_layouts.hpp>
 
 void test_odr_use( int const* );
 
@@ -28,7 +29,9 @@ void f2()
 
     test<float>();
     test<double>();
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test<long double>();
+    #endif
 
 #ifdef BOOST_CHARCONV_HAS_INT128
 
--- a/libs/charconv/test/roundtrip.cpp
+++ b/libs/charconv/test/roundtrip.cpp
@@ -347,6 +347,7 @@ template<typename FPType> int64_t Distance(FPType y, FPType x)
     return ToOrdinal(y) - ToOrdinal(x);
 }
 
+#ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
 template <> void test_roundtrip<long double>(long double value)
 {
     char buffer[ 256 ];
@@ -381,6 +382,7 @@ template <> void test_roundtrip<long double>(long double value)
         // LCOV_EXCL_STOP
     }
 }
+#endif
 
 // floating point types, boundary values
 
@@ -601,7 +603,7 @@ int main()
     #endif
 
     // long double
-    #if !(BOOST_CHARCONV_LDBL_BITS == 128)
+    #if !(BOOST_CHARCONV_LDBL_BITS == 128) && !defined(BOOST_MATH_UNSUPPORTED_LONG_DOUBLE)
 
     {
         long double const ql = std::pow( 1.0L, -64 );
--- a/libs/charconv/test/to_chars_float.cpp
+++ b/libs/charconv/test/to_chars_float.cpp
@@ -202,7 +202,7 @@ int main()
     non_finite_values<double>(boost::charconv::chars_format::hex, 2);
 
     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57484
-    #if !(defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ < 9 && defined(__i686__))
+    #if !(defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ < 9 && defined(__i686__)) && !defined(BOOST_MATH_UNSUPPORTED_LONG_DOUBLE)
     non_finite_values<long double>();
     #endif
 
--- a/libs/charconv/test/to_chars_float_STL_comp.cpp
+++ b/libs/charconv/test/to_chars_float_STL_comp.cpp
@@ -212,7 +212,10 @@ int main()
     // General format
     random_test<float>();
     random_test<double>();
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     random_test<long double>();
+    #endif
+
     test_spot<double>(0.0);
     test_spot<double>(-0.0);
 
@@ -224,7 +227,9 @@ int main()
     // Scientific
     random_test<float>(boost::charconv::chars_format::scientific);
     random_test<double>(boost::charconv::chars_format::scientific);
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     random_test<long double>(boost::charconv::chars_format::scientific);
+    #endif
     test_spot<double>(0.0, boost::charconv::chars_format::scientific);
     test_spot<double>(-0.0, boost::charconv::chars_format::scientific);
 
@@ -237,14 +242,20 @@ int main()
     // Hex
     random_test<float>(boost::charconv::chars_format::hex);
     random_test<double>(boost::charconv::chars_format::hex);
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     random_test<long double>(boost::charconv::chars_format::hex);
+    #endif
 
     #if !defined(_LIBCPP_VERSION)
+
     random_test<float>(boost::charconv::chars_format::hex, -1e5F, 1e5F);
     random_test<double>(boost::charconv::chars_format::hex, -1e5, 1e5);
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     random_test<long double>(boost::charconv::chars_format::hex, -1e5L, 1e5L);
     #endif
 
+    #endif
+
     test_spot<double>(-9.52743282403084637e+306, boost::charconv::chars_format::hex);
     test_spot<double>(-9.52743282403084637e-306, boost::charconv::chars_format::hex);
     test_spot<double>(-9.52743282403084637e+305, boost::charconv::chars_format::hex);
@@ -261,13 +272,16 @@ int main()
     // Various non-finite values
     non_finite_test<float>();
     non_finite_test<double>();
-    non_finite_test<long double>();
     non_finite_test<float>(boost::charconv::chars_format::scientific);
     non_finite_test<double>(boost::charconv::chars_format::scientific);
-    non_finite_test<long double>(boost::charconv::chars_format::scientific);
     non_finite_test<float>(boost::charconv::chars_format::hex);
     non_finite_test<double>(boost::charconv::chars_format::hex);
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
+    non_finite_test<long double>();
+    non_finite_test<long double>(boost::charconv::chars_format::scientific);
     non_finite_test<long double>(boost::charconv::chars_format::hex);
+    #endif
 
     #if (defined(__GNUC__) && __GNUC__ >= 11) || (defined(_MSC_VER) && _MSC_VER >= 1924)
     // Selected additional values
@@ -288,7 +302,10 @@ int main()
     // Reported in issue #93
     test_spot<float>(3.3F);
     test_spot<double>(3.3);
+
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     test_spot<long double>(3.3L);
+    #endif
 
     return boost::report_errors();
 }
--- a/libs/charconv/test/to_chars_sprintf.cpp
+++ b/libs/charconv/test/to_chars_sprintf.cpp
@@ -627,6 +627,7 @@ int main()
 
     // long double
 
+    #ifndef BOOST_MATH_UNSUPPORTED_LONG_DOUBLE
     {
         for( int i = 0; i < N; ++i )
         {
@@ -665,6 +666,7 @@ int main()
 
         test_sprintf_bv_fp<long double>();
     }
+    #endif
 
     return boost::report_errors();
 }
-- 
2.45.2