Use Perl for filtering MAKEFLAGS properly

Requires moving the checkflags code into CONFIG_BASE
as that's where FIND_TOOL gets defined.

Fixes epics-base#545

configure/CONFIG_BASE

@@ -49,6 +49,7 @@ PODTOHTML_pl     = $(TOOLS)/podToHtml.pl
 PODTOHTML_dep    = $(PODTOHTML_pl) $(call FIND_PM,EPICS/PodHtml.pm)
 PODTOHTML        = $(PERL) $(PODTOHTML_pl)
 CONVERTRELEASE   = $(PERL) $(call FIND_TOOL,convertRelease.pl)
+FILTERMAKEFLAGS  = $(PERL) $(call FIND_TOOL,filterMakeflags.pl)
 FULLPATHNAME     = $(PERL) $(TOOLS)/fullPathName.pl
 GENVERSIONHEADER = $(PERL) $(TOOLS)/genVersionHeader.pl $(QUIET_FLAG) $(QUESTION_FLAG)
 
@@ -65,6 +66,24 @@ INSTALL_LIBRARY = $(INSTALL)
 MKMF       = $(PERL) $(TOOLS)/mkmf.pl
 REPLACEVAR = $(PERL) $(TOOLS)/replaceVAR.pl
 
+#---------------------------------------------------------------
+# How to portably check the flags to make
+# GNUmake versions before 4.0 gave different values
+makeflags := $(shell $(FILTERMAKEFLAGS) $(MAKEFLAGS))
+define checkflags
+  make-$1 := $(findstring $1,$(makeflags))
+endef
+# This is extensible to most single letter flags:
+$(foreach flag,s q, $(eval $(call checkflags,$(flag))))
+
+# Silent builds - suppress messages during 'make -s'
+NOP = :
+ECHO = @$(if $(make-s),$(NOP),echo)
+QUIET_FLAG := $(if $(make-s),-q,)
+
+# Convert 'make -q' flag into '-i' for genVersionHeader.pl
+QUESTION_FLAG := $(if $(make-q),-i,)
+
 #---------------------------------------------------------------
 # tools for cleaning out unwanted files
 CVSCLEAN = $(call FIND_TOOL,cvsclean.pl)

configure/CONFIG_COMMON

@@ -81,23 +81,6 @@ FINAL_LOCATION              = $(INSTALL_ABSOLUTE)
 # IOC's view of install path
 IOCS_APPL_TOP               = $(INSTALL_ABSOLUTE)
 
-#-------------------------------------------------------
-# How to portably check the flags to make
-makeflags := $(firstword $(filter-out -,$(filter-out --%,$(MAKEFLAGS))))
-define checkflags
-  make-$1 := $(findstring $1,$(makeflags))
-endef
-# This is extensible to most single letter flags:
-$(foreach flag,s q, $(eval $(call checkflags,$(flag))))
-
-# Silent builds - suppress messages during 'make -s'
-NOP = :
-ECHO = @$(if $(make-s),$(NOP),echo)
-QUIET_FLAG := $(if $(make-s),-q,)
-
-# Convert 'make -q' flag into '-i' for genVersionHeader.pl
-QUESTION_FLAG := $(if $(make-q),-i,)
-
 #-------------------------------------------------------
 ifdef T_A
 

src/tools/Makefile

@@ -29,6 +29,7 @@ PERL_SCRIPTS += depclean.pl
 PERL_SCRIPTS += dos2unix.pl
 PERL_SCRIPTS += epicsProve.pl
 PERL_SCRIPTS += expandVars.pl
+PERL_SCRIPTS += filterMakeflags.pl
 PERL_SCRIPTS += fullPathName.pl
 PERL_SCRIPTS += installEpics.pl
 PERL_SCRIPTS += makeAPIheader.pl

src/tools/filterMakeflags.pl

@@ -0,0 +1,15 @@
+#!/bin/env perl
+#
+# Filter all versions of GNU Make's MAKEFLAGS variable to return
+# only the single-letter flags. The content differed slightly
+# between 3.81, 3.82 and 4.0; Apple still ship 3.81.
+
+use strict;
+
+my @flags;
+foreach (@ARGV) {
+    last if m/^--$/ or m/\w+=/;
+    next if m/^--/ or m/^-$/;
+    push @flags, $_;
+};
+print join(' ', @flags);