Gentoo specific to go with `tc-export_build_env BUILD_CC` + respect flags.
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -96,3 +96,3 @@
 makeopts: makeopts.c
-	$(CC) -o makeopts makeopts.c
+	$(BUILD_CC) $(BUILD_CFLAGS) $(BUILD_CPPFLAGS) $(BUILD_LDFLAGS) -o makeopts makeopts.c
 
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -643,3 +643,3 @@
 makeopts: makeopts.c
-	$(CC) -o makeopts makeopts.c
+	$(BUILD_CC) $(BUILD_CFLAGS) $(BUILD_CPPFLAGS) $(BUILD_LDFLAGS) -o makeopts makeopts.c