Fixes definition of CC variable
Fix by David Denoncin
https://bugs.gentoo.org/732432

--- a/Makefile       2020-07-24 16:54:47.986847005 +0200
+++ b/Makefile    2020-07-24 16:55:13.386845781 +0200
@@ -147,7 +147,7 @@
 # For Sun Solaris 2.x w/SparcCompilerC (cc), use CC = cc.
 # For Sun Solaris 2.x w/GNU gcc, use CC = gcc
 #CC = gcc
-CC = /usr/bin/gcc
+CC ?=

 # For HPUX, use LIBS = -L/usr/lib/X11R4 -lX11 -lm -lcurses -ltermcap
 # For AIX or OSF/1, add -lbsd