cflags.SH - add commentary

Add comments to the top of cflags.SH to explain what it does.
Also make it output comments at the top of the generated cflags
script explaining that its auto-generated.

diff --git a/cflags.SH b/cflags.SH
index a80eb5d..84e3187 100755 (executable)
--- a/cflags.SH
+++ b/cflags.SH
@@ -1,5 +1,17 @@
 #!/bin/sh
 
+# Generate the cflags script, which is used to determine what cflags
+# to pass to the compiler.
+# We create a temporary test c program and repeatedly compile it with
+# various candidate flags, and from the compiler output, determine what
+# flags are supported.
+# From this we initialise the following variables in the cflags script:
+#
+#   $warn
+#   $stdflags
+#   $extra
+#   $_exe
+
 case $PERL_CONFIG_SH in
 '')
        if test -f config.sh; then TOP=.;
@@ -210,6 +222,11 @@ rm -f cflags
 $spitshell >cflags <<!GROK!THIS!
 $startsh
 
+# !!!!!!!   DO NOT EDIT THIS FILE   !!!!!!!
+
+# This file is generated by cflags.SH
+
+
 # Extra warnings, used e.g. for gcc.
 warn="$warn"
 # Extra standardness.