Since 776c012c6e3b6dd66aeeff851aedb48851f93975, we build GCC s.t. it has
-stdlib= if one wishes to use it for advanced cases. Unfortunately, the
libprojectm configure script automagically uses -stdlib=libc++ if available
which is completely wrong and breaks the Qt check.
--- a/configure.ac
+++ b/configure.ac
@@ -153,11 +153,6 @@ AC_PREFIX_DEFAULT([/usr/local])
 
 AC_PROG_MKDIR_P
 
-AS_IF([echo ${host} | grep -Fq android], [],
-  [AX_CHECK_COMPILE_FLAG([-stdlib=libc++], [
-                        CXXFLAGS="$CXXFLAGS -stdlib=libc++"])
-])
-
 AX_CHECK_COMPILE_FLAG([-std=c++14], [
                         CXXFLAGS="$CXXFLAGS -std=c++14"])