[PATCH] gcc/Makefile.in: Fix install-info target if BUILD_INFO is empty

[Christophe Lyon <christophe.lyon@linaro.org>]

BUILD_INFO is currently a byproduct of checking makeinfo
presence/version.  INSTALL_INFO used to be defined similarly, but was
removed in 2000 (!) by commit 17db658241d18cf6db59d31bc2d6eac96e9257df
(svn r38141).

In order to save build time, our CI overrides BUILD_INFO="", which
works when invoking 'make all' but not for 'make install' in case some
info files need an update.

I noticed this when testing a patch posted on the gcc-patches list,
leading to an error at 'make install' time after updating tm.texi (the
build reported 'new text' in tm.texi and stopped).  This is because
'install' depends on 'install-info', which depends on
$(DESTDIR)$(infodir)/gccint.info (among others).

This patch makes the 'install-info' dependency in 'install'
conditioned by BUILD_INFO.

2024-02-05  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/
	* Makefile.in: Use install-info only if BUILD_INFO is not empty.
---
 gcc/Makefile.in | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 4d38b162307..6cb564cfd35 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -817,7 +817,6 @@ INSTALL_HEADERS=install-headers install-mkheaders
 
 # Control whether Info documentation is built and installed.
 BUILD_INFO = @BUILD_INFO@
-INSTALL_INFO = @INSTALL_INFO@
 
 # Control flags for @contents placement in HTML output
 MAKEINFO_TOC_INLINE_FLAG = @MAKEINFO_TOC_INLINE_FLAG@
@@ -3786,9 +3785,13 @@ maintainer-clean:
 # Install the driver last so that the window when things are
 # broken is small.
 install: install-common $(INSTALL_HEADERS) \
-    install-cpp install-man $(INSTALL_INFO) install-@POSUB@ \
+    install-cpp install-man install-@POSUB@ \
     install-driver install-lto-wrapper install-gcc-ar
 
+ifneq ($(BUILD_INFO),)
+install: install-info
+endif
+
 ifeq ($(enable_plugin),yes)
 install: install-plugin
 endif
-- 
2.34.1