diff --git a/wscript b/wscript
index f3b268f0..cd8dbae7 100644
--- a/wscript
+++ b/wscript
@@ -198,6 +198,10 @@ def configure(conf):
 	conf.env.append_unique('CXXFLAGS', cxxflags)
 	conf.env.append_unique('LINKFLAGS', linkflags)
 
+	# check if we can use C99 tgmath
+	if conf.check_cc(header_name='tgmath.h', mandatory=False):
+		conf.env.define('HAVE_TGMATH_H', 1)
+
 	if conf.env.COMPILER_CC == 'msvc':
 		conf.define('_CRT_SECURE_NO_WARNINGS', 1)
 		conf.define('_CRT_NONSTDC_NO_DEPRECATE', 1)