branch master updated: * INSTALL: elaborate on PERL_EXT_* variables for building XS modules, why they are needed and how to override them when running make.

[Gavin D. Smith]

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gavin pushed a commit to branch master
in repository texinfo.

The following commit(s) were added to refs/heads/master by this push:
     new 1d21ccf750 * INSTALL: elaborate on PERL_EXT_* variables for building 
XS modules, why they are needed and how to override them when running make.
1d21ccf750 is described below

commit 1d21ccf750430d778cbde95958456e2fb53b772e
Author: Gavin Smith <gavinsmith0123@gmail.com>
AuthorDate: Wed Nov 22 20:38:04 2023 +0000

    * INSTALL: elaborate on PERL_EXT_* variables for building
    XS modules, why they are needed and how to override them when
    running make.
---
 ChangeLog |  6 ++++++
 INSTALL   | 15 ++++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5daebfba94..c693739a8a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2023-11-22  Gavin Smith <gavinsmith0123@gmail.com>
+
+       * INSTALL: elaborate on PERL_EXT_* variables for building
+       XS modules, why they are needed and how to override them when
+       running make.
+
 2023-11-22  Gavin Smith <gavinsmith0123@gmail.com>
 
        * tp/Texinfo/XS/Makefile.am,
diff --git a/INSTALL b/INSTALL
index 0e3f38f1c3..bbaf2ffc76 100644
--- a/INSTALL
+++ b/INSTALL
@@ -59,9 +59,18 @@ Installation notes specific to Texinfo:
   attempt to detect whether such modules can be built and loaded on your
   installation.  If you want to disable the use of XS modules, you can
   give the --disable-perl-xs flag to `configure'; likewise, to use them
-  without checking, give the --enable-perl-xs flag.  Some of the
-  environment variables listed in the output of `./configure --help' may
-  be of use for building the XS modules.
+  without checking, give the --enable-perl-xs flag.
+
+  When `configure' is running in the XS subdirectory, instead of the
+  standard CC, CFLAGS, LDFLAGS etc., it uses special variables with a
+  PERL_EXT_ prefix.  These are all listed in the output of `configure
+  --help'.  This is necessary because it is possible that the C compiler
+  being used to compile Perl extension modules is a different compiler
+  to that used for the rest of the package.  (However, if you need to
+  override these variables when running `make', use the unprefixed
+  variants, e.g. CFLAGS instead of PERL_EXT_CFLAGS.  Exception: you
+  cannot override CPPFLAGS this way as gnulib uses this variable.)
+
       After building the program, the use of XS modules can be
   controlled with the `TEXINFO_XS' environment variable, which may be
   useful for troubleshooting.  Set TEXINFO_XS=debug to print some