bug#56272: [PATCH] fix configure.ac quoting of AC_CHECK_LIB's 2nd arg

[Jim Meyering]

I tried to build latest emacs bootstrapped with the latest autoconf and
hit a failure due to inadequate quoting in configure.ac. This fixes
three such problems:

>From 5cbeba4d1f2102066b3d0c327e289c6a840b114b Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@fb.com>
Date: Sun, 26 Jun 2022 21:26:01 -0700
Subject: [PATCH] fix configure.ac quoting of AC_CHECK_LIB's 2nd arg

Running an autoconf-head-generated configure, would fail like this:
  /emacs/configure: line 18002: syntax error near unexpected token `;;'
  /emacs/configure: line 18002: `  ;;'
That is due to under-quoting of AC_CHECK_LIB's second argument, which led to
the comma in an embedded string being interpreted as paramater-delimiting.
* configure.ac: Quote the second arg of each AC_CHECK_LIB invocation.
---
 configure.ac | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index c91b7de322..17f86627a7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3622,7 +3622,7 @@ AC_DEFUN
        CFLAGS="$CFLAGS $XFT_CFLAGS"
        LIBS="$XFT_LIBS $LIBS"
        AC_CHECK_HEADER(X11/Xft/Xft.h,
-         AC_CHECK_LIB(Xft, XftFontOpen, HAVE_XFT=yes, , $XFT_LIBS) , ,
+          [AC_CHECK_LIB(Xft, XftFontOpen, HAVE_XFT=yes, , $XFT_LIBS)] , ,
           [[#include <X11/X.h>]])

        if test "${HAVE_XFT}" = "yes"; then
@@ -3818,7 +3818,7 @@ AC_DEFUN
 XCB_LIBS=
 if test "${HAVE_X11}" = "yes"; then
   AC_CHECK_HEADER(X11/Xlib-xcb.h,
-    AC_CHECK_LIB(xcb, xcb_translate_coordinates, HAVE_XCB=yes))
+    [AC_CHECK_LIB(xcb, xcb_translate_coordinates, HAVE_XCB=yes)])
   if test "${HAVE_XCB}" = "yes"; then
     AC_CHECK_LIB(X11-xcb, XGetXCBConnection, HAVE_X11_XCB=yes)
     if test "${HAVE_X11_XCB}" = "yes"; then
@@ -4597,7 +4597,7 @@ AC_DEFUN
 HAVE_XSYNC=no
 if test "${HAVE_X11}" = "yes"; then
    AC_CHECK_HEADER(X11/extensions/sync.h,
-     AC_CHECK_LIB(Xext, XSyncQueryExtension, HAVE_XSYNC=yes),
+     [AC_CHECK_LIB(Xext, XSyncQueryExtension, HAVE_XSYNC=yes)],
      [], [#include <X11/Xlib.h>])

   if test "${HAVE_XSYNC}" = "yes"; then
-- 
2.37.0.rc2