[newlib-cygwin] libgloss: document & localize custom multi-do rule

[Michael Frysinger <vapier@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=e56bdf902bd77ef66f25985a8ae3b0ecbc4ef196

commit e56bdf902bd77ef66f25985a8ae3b0ecbc4ef196
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Feb 18 23:26:51 2022 -0500

    libgloss: document & localize custom multi-do rule
    
    The multi-build.in file in libgloss duplicates common multilib logic
    in the root source tree.  Document it a bit, and rename the rule so
    it doesn't clash with the common multi-do rule.  This will let us use
    them in the same makefile so we can merge aarch64/ & arm/ up (as the
    only targets that use this local multi-build.in atm).

Diff:
---
 libgloss/aarch64/Makefile.in | 8 ++++----
 libgloss/arm/Makefile.in     | 8 ++++----
 libgloss/multi-build.in      | 7 ++++++-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/libgloss/aarch64/Makefile.in b/libgloss/aarch64/Makefile.in
index 82a0e3717..e84aa6927 100644
--- a/libgloss/aarch64/Makefile.in
+++ b/libgloss/aarch64/Makefile.in
@@ -152,7 +152,7 @@ $(RDIMON_BSP): $(RDIMON_OBJS)
 	${RANLIB} $@
 
 # Multilib support.
-.PHONY:  multi-do all-multi clean-multi install-multi
+.PHONY:  libgloss-multi-do all-multi clean-multi install-multi
 
 all-recursive: all-multi
 clean-recursive: clean-multi
@@ -160,13 +160,13 @@ install-recursive: install-multi
 
 # The $(MAKE) comments below are to enable parallel building.
 all-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=all multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=all libgloss-multi-do
 
 clean-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=clean multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=clean libgloss-multi-do
 
 install-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=install multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=install libgloss-multi-do
 
 clean mostlyclean:
 	rm -f a.out core *.i *.o *-test *.srec *.dis *.x $(SIM_BSP) ${RDIMON_SCRIPTS}
diff --git a/libgloss/arm/Makefile.in b/libgloss/arm/Makefile.in
index 9201a1b0c..45d889409 100644
--- a/libgloss/arm/Makefile.in
+++ b/libgloss/arm/Makefile.in
@@ -175,7 +175,7 @@ $(RDIMON_BSP): $(RDIMON_OBJS)
 	${RANLIB} $@
 
 # Multilib support.
-.PHONY:  multi-do all-multi clean-multi install-multi
+.PHONY:  libgloss-multi-do all-multi clean-multi install-multi
 
 all-recursive: all-multi
 clean-recursive: clean-multi
@@ -183,13 +183,13 @@ install-recursive: install-multi
 
 # The $(MAKE) comments below are to enable parallel building.
 all-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=all multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=all libgloss-multi-do
 
 clean-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=clean multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=clean libgloss-multi-do
 
 install-multi:
-	$(MAKE) $(AM_MAKEFLAGS) DO=install multi-do
+	$(MAKE) $(AM_MAKEFLAGS) DO=install libgloss-multi-do
 
 clean mostlyclean:
 	rm -f a.out core *.i *.o *-test *.srec *.dis *.x $(SIM_BSP) $(IQ80310_BSP)
diff --git a/libgloss/multi-build.in b/libgloss/multi-build.in
index 52aeeec26..80919ed6f 100644
--- a/libgloss/multi-build.in
+++ b/libgloss/multi-build.in
@@ -1,8 +1,13 @@
+# This is like ../multilib.am and ../config-ml.in and ../config/multi.m4 mashed
+# into one file.  It relies on some custom hardcoded MULTI* variables in the
+# respective Makefile.in instead of dynamic compiler probing that ../multilib.am
+# does.
+
 PWD_COMMAND=$${PWDCMD-pwd}
 
 # FIXME: There should be an @-sign in front of the `if'.
 # Leave out until this is tested a bit more.
-multi-do:
+libgloss-multi-do:
 	if [ -z "$(MULTIDIRS)" ]; then \
 	  true; \
 	else \