From 54400c2e0c86acce56e13acc260cc8bf7ee28719 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dag-Erling=20Sm=C3=B8rgrav?= <des@des.dev>
Date: Fri, 3 May 2024 01:20:31 +0200
Subject: [PATCH] autotools: Simplify handling of `SIZEOF_VOID_P`.

---
 expat/buildconf.sh                            | 23 +------------------
 .../autotools/expat-config-version.cmake.in   |  6 ++---
 expat/configure.ac                            | 16 +++++--------
 3 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/expat/buildconf.sh b/expat/buildconf.sh
index 5e2b3269..1b4dc699 100755
--- a/expat/buildconf.sh
+++ b/expat/buildconf.sh
@@ -31,25 +31,4 @@
 
 set -e
 
-# File expat_config.h.in (as generated by autoheader by autoreconf) contains
-# macro SIZEOF_VOID_P which is (1) not really needed by Expat as of today and
-# (2) a problem to "multilib" systems with one shared installed
-# /usr/include/expat_config.h for two Expats with different "void *" sizes
-# installed in e.g. /usr/lib32 and /usr/lib64.  Hence we patch macro
-# SIZEOF_VOID_P out of template expat_config.h.in so that configure will
-# not put SIZEOF_VOID_P in the eventual expat_config.h.
-patch_expat_config_h_in() {
-    local filename="$1"
-    local sizeof_void_p_line_number="$(grep -F -n SIZEOF_VOID_P "${filename}" | awk -F: '{print $1}')"
-    [[ ${sizeof_void_p_line_number} =~ ^[0-9]+$ ]]  # cheap assert
-    local first_line_to_delete=$(( sizeof_void_p_line_number - 1 ))
-    local last_line_to_delete=$(( sizeof_void_p_line_number + 1 ))
-    # Note: Avoiding "sed -i" only for macOS portability.
-    local tempfile="$(mktemp)"
-    sed "${first_line_to_delete},${last_line_to_delete}d" "${filename}" > "${tempfile}"
-    mv "${tempfile}" "${filename}"
-}
-
-autoreconf --warnings=all --install --verbose "$@"
-
-patch_expat_config_h_in expat_config.h.in
+exec autoreconf --warnings=all --install --verbose "$@"
diff --git a/expat/cmake/autotools/expat-config-version.cmake.in b/expat/cmake/autotools/expat-config-version.cmake.in
index f880e638..17ab1924 100644
--- a/expat/cmake/autotools/expat-config-version.cmake.in
+++ b/expat/cmake/autotools/expat-config-version.cmake.in
@@ -53,13 +53,13 @@ endif()
 
 
 # if the installed or the using project don't have CMAKE_SIZEOF_VOID_P set, ignore it:
-if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "" OR "@ac_cv_sizeof_void_p@" STREQUAL "")
+if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "" OR "@SIZEOF_VOID_P@" STREQUAL "")
   return()
 endif()
 
 # check that the installed version has the same 32/64bit-ness as the one which is currently searching:
-if(NOT CMAKE_SIZEOF_VOID_P STREQUAL "@ac_cv_sizeof_void_p@")
-  math(EXPR installedBits "@ac_cv_sizeof_void_p@ * 8")
+if(NOT CMAKE_SIZEOF_VOID_P STREQUAL "@SIZEOF_VOID_P@")
+  math(EXPR installedBits "@SIZEOF_VOID_P@ * 8")
   set(PACKAGE_VERSION "${PACKAGE_VERSION} (${installedBits}bit)")
   set(PACKAGE_VERSION_UNSUITABLE TRUE)
 endif()
diff --git a/expat/configure.ac b/expat/configure.ac
index 9d28d79a..1d0954b7 100644
--- a/expat/configure.ac
+++ b/expat/configure.ac
@@ -403,7 +403,6 @@ LIBDIR_BASENAME="$(basename "${libdir}")"
 SO_MAJOR="$(expr "${LIBCURRENT}" - "${LIBAGE}")"
 SO_MINOR="${LIBAGE}"
 SO_PATCH="${LIBREVISION}"
-AC_CHECK_SIZEOF([void *])  # sets ac_cv_sizeof_void_p
 AC_SUBST([EXPAT_ATTR_INFO])
 AC_SUBST([EXPAT_DTD])
 AC_SUBST([EXPAT_LARGE_SIZE])
@@ -416,16 +415,13 @@ AC_SUBST([LIBDIR_BASENAME])
 AC_SUBST([SO_MAJOR])
 AC_SUBST([SO_MINOR])
 AC_SUBST([SO_PATCH])
-AC_SUBST([ac_cv_sizeof_void_p])
 
-dnl Protect against generating an expat_config.h that would break multilib
-AS_IF([grep -F -q SIZEOF_VOID_P "${srcdir}"/expat_config.h.in],
-  [AC_MSG_ERROR(
-    [Plain autoreconf/autoheader does not cut it,
-                  please use ./buildconf.sh or imitate its effect
-                  through other means, so that file expat_config.h.in
-                  no longer defines macro SIZEOF_VOID_P, as that would
-                  break multilib support.  Thank you.])])
+dnl The canonical way of doing this is AC_CHECK_SIZEOF(void *), but
+dnl that adds SIZEOF_VOID_P to expat_config.h.in, making it difficult
+dnl to have 32-bit and 64-bit versions of libexpat installed on the
+dnl same system with a single, shared copy of the header.
+AC_COMPUTE_INT(SIZEOF_VOID_P, [sizeof(void *)])
+AC_SUBST([SIZEOF_VOID_P])
 
 dnl write the Automake flags we set
 AC_SUBST([AM_CPPFLAGS])