Correct comments wrt CC in example Makefile

A long while back I improved the Makefiles to allow for compiler
specific flags so that they don't have to be only "clang" or "gcc". This
is because in some systems gcc is actually clang (macOS does this). Also
if someone wants to use a different version or path then they can do so
with the right flags enabled. Before that change it would not work
right.

The comments suggested these flags will only be set when CC is exactly
"clang" or "gcc". This has been corrected.

next/Makefile.example

@@ -134,10 +134,11 @@ CC= cc
 #
 ifeq "$(findstring $(CLANG),${CC})" "$(CLANG)"
 #
-# NOTE: This code is only invoked when CC is "clang"
-#       such as when you use the make command line:
+# NOTE: This code is only invoked when CC contains "clang"
+#       such as when you use the make command lines like:
 #
 #           make all CC=clang
+#           make all CC=clang-mp-12
 #
 CSILENCE+=
 #
@@ -149,10 +150,11 @@ endif
 #
 ifeq "$(findstring $(GCC),${CC})" "$(GCC)"
 #
-# NOTE: This code is only invoked when CC is "gcc"
-#       such as when you use the make command line:
+# NOTE: This code is only invoked when CC contains "gcc"
+#       such as when you use the make command lines like:
 #
 #    make all CC=gcc
+#    make all CC=gcc-15
 #
 CSILENCE+=
 #
@@ -184,6 +186,7 @@ DATA=
 # NOTE: Add any new Makefile variables your code might need below.
 #
 # Example: WIDTH= 120
+#
 
 
 #################