unset any potentially disturbing environment variables

build_mingw_cross_env.sh

@@ -73,6 +73,20 @@ set -ex
 #---
 
 
+#---
+#   Portability
+#---
+
+unset AR CC CFLAGS CROSS CXX CXXFLAGS EXEEXT 
+unset LD LIBS NM PKG_CONFIG RANLIB STRIP
+
+MAKE=gmake
+$MAKE --version >&2 || MAKE=make
+
+SED=gsed
+$SED  --version >&2 || SED=sed
+
+
 #---
 #   Configuration
 #---
@@ -128,17 +142,6 @@ VERSION_pdflib_lite=7.0.1
 VERSION_libowfat=0.25
 
 
-#---
-#   Portability
-#---
-
-MAKE=gmake
-$MAKE --version >&2 || MAKE=make
-
-SED=gsed
-$SED  --version >&2 || SED=sed
-
-
 #---
 #   Main
 #---