Index: Project/GNU/Library/Makefile.am
--- Project/GNU/Library/Makefile.am.orig
+++ Project/GNU/Library/Makefile.am
@@ -313,6 +313,8 @@ pkgconfig_DATA = libmediainfo.pc
 
 AM_CXXFLAGS = -std=c++11
 AM_CPPFLAGS = -I../../../Source -I../../../../ZenLib/Source
+# Do not pick up external fmt from ${prefix}/include
+AM_CPPFLAGS += -I../../../Source/ThirdParty
 
 TESTS_DIR = test
 
