Improve variable parsing when generating MINFO

Before this change, variables for which a '=' appeared in the assignment would
be parsed as the entire string up until the final '='. For example:

  BUILD_CMD=shlib_target=; if [ -n "$(SHARED_LIBS)" ]; then \

would result in the variable name "BUILD_CMD=shlib_target". This doesn't
appear to harm the current generation of MINFO, but creates problems for other
Makefile-related work I'm attempting.

Change-Id: I1f3a606d67fd5464bb459e8f36c23b3e967b77e1
Signed-off-by: NMike Bland <mbland@acm.org>
Signed-off-by: NGeoff Thorpe <geoff@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>

util/files.pl

@@ -4,7 +4,7 @@
 # It is basically a list of all variables from the passed makefile
 #
 
-while ($ARGV[0] =~ /^(\S+)\s*=(.*)$/)
+while ($ARGV[0] =~ /^([^\s=]+)\s*=\s*(.*)$/)
 	{
 	$sym{$1} = $2;
 	shift;
@@ -15,7 +15,7 @@ while (<>)
 	{
 	chop;
 	s/#.*//;
-	if (/^(\S+)\s*=\s*(.*)$/)
+	if (/^([^\s=]+)\s*=\s*(.*)$/)
 		{
 		$o="";
 		($s,$b)=($1,$2);

util/mkfiles.pl

@@ -110,7 +110,7 @@ while (<IN>)
 	{
 	chop;
 	s/#.*//;
-	if (/^(\S+)\s*=\s*(.*)$/)
+	if (/^([^\s=]+)\s*=\s*(.*)$/)
 		{
 		$o="";
 		($s,$b)=($1,$2);