Fix libm (and ncurses) underlinking issues.
https://bugs.gentoo.org/show_bug.cgi?id=529490

--- mpfc-1.3.8.1/configure.ac
+++ mpfc-1.3.8.1/configure.ac
@@ -13,13 +13,13 @@
 COMMON_LIBS=""
 AC_SUBST(COMMON_LIBS)
 
+dnl Check for libm for rintf()
+AC_SEARCH_LIBS([rintf], [m], [], [
+	AC_MSG_ERROR([unable to find the rintf() function])
+])
+
 # Check for ncurses
-LIBS_save=$LIBS
-AC_CHECK_HEADERS([curses.h],,[AC_MSG_ERROR(*** Can't find curses.h ***)])
-AC_CHECK_LIB(ncursesw, waddch,,[AC_MSG_ERROR(*** Can't find ncurses library ***)])
-CURSES_LIBS="-lncursesw"
-AC_SUBST(CURSES_LIBS)
-LIBS=$LIBS_save
+PKG_CHECK_MODULES([CURSES], [ncursesw])
 
 # Check for pthread
 LIBS_save=$LIBS
--- mpfc-1.3.8.1/libmpfcwnd/Makefile.am
+++ mpfc-1.3.8.1/libmpfcwnd/Makefile.am
@@ -1,3 +1,4 @@
+AM_CPPFLAGS = @CURSES_CFLAGS@
 lib_LTLIBRARIES = libmpfcwnd.la
 libmpfcwndhdrdir = $(includedir)/mpfc/libmpfcwnd
 libmpfcwndhdr_HEADERS = wnd.h wnd_print.h wnd_msg.h wnd_kbd.h \