See https://bugs.gentoo.org/852830

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -234,6 +234,7 @@
   add_subdirectory(java)
 endif()
 
+option(BUILD_SERVER "Build TigerVNC server" ON)
 option(BUILD_VIEWER "Build TigerVNC viewer" ON)
 if(BUILD_VIEWER)
   # Check for FLTK
@@ -276,7 +277,7 @@
 endif()
 
 # Check for PAM library
-if(UNIX AND NOT APPLE)
+if(BUILD_SERVER AND UNIX AND NOT APPLE)
   check_include_files(security/pam_appl.h HAVE_PAM_H)
   set(CMAKE_REQUIRED_LIBRARIES -lpam)
   check_function_exists(pam_start HAVE_PAM_START)
@@ -315,9 +316,6 @@
   add_subdirectory(media)
 endif()
 
-add_subdirectory(tests)
-
-
 if(BUILD_VIEWER)
   add_subdirectory(release)
 endif()
--- a/common/rfb/CMakeLists.txt
+++ b/common/rfb/CMakeLists.txt
@@ -88,7 +88,7 @@
   target_sources(rfb PRIVATE WinPasswdValidator.cxx)
 endif(WIN32)
 
-if(UNIX AND NOT APPLE)
+if(BUILD_SERVER AND UNIX AND NOT APPLE)
   target_sources(rfb PRIVATE UnixPasswordValidator.cxx pam.c)
   target_link_libraries(rfb ${PAM_LIBS})
 endif()
--- a/unix/CMakeLists.txt
+++ b/unix/CMakeLists.txt
@@ -1,6 +1,8 @@
 add_subdirectory(tx)
 add_subdirectory(common)
-add_subdirectory(vncconfig)
-add_subdirectory(vncpasswd)
-add_subdirectory(vncserver)
-add_subdirectory(x0vncserver)
+if(BUILD_SERVER)
+	add_subdirectory(vncconfig)
+	add_subdirectory(vncpasswd)
+	add_subdirectory(vncserver)
+	add_subdirectory(x0vncserver)
+endif()