--- configure.ac.orig	2026-02-05 12:41:56 UTC
+++ configure.ac
@@ -14,8 +14,6 @@ define([ucx_ver_extra], )   # Extra version string. Em
 define([ucx_ver_patch], 0)  # Patch version. Increased for a bugfix release.
 define([ucx_ver_extra], )   # Extra version string. Empty for a general release.
 
-define([ts], esyscmd([sh -c "date +%Y%m%d%H%M%S"]))
-
 # This is the API version (see libtool library versioning)
 # http://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
 # current:rev:age
@@ -31,14 +29,20 @@ AC_CONFIG_HEADERS([config.h])
 AC_USE_SYSTEM_EXTENSIONS
 AC_CONFIG_HEADERS([config.h])
 
-AC_CHECK_PROG(GITBIN, git, yes)
-AS_IF([test x"${GITBIN}" = x"yes"],
-      [# remove preceding "refs/heads/" (11 characters) for symbolic ref
-       AC_SUBST(SCM_BRANCH,  esyscmd([sh -c 'git symbolic-ref --quiet   HEAD | sed "s/^.\{11\}//"']))
-       AC_SUBST(SCM_VERSION, esyscmd([sh -c 'git rev-parse    --short=7 HEAD']))],
-      [AC_SUBST(SCM_BRANCH,  "<unknown>")
-       AC_SUBST(SCM_VERSION, "0000000")])
+AC_PATH_PROG([GIT], [git], [:])
 
+SCM_BRANCH="<unknown>"
+SCM_VERSION="0000000"
+
+AS_IF([test -d "${srcdir}/.git" && test "x$GIT" != "x:" && \
+       $GIT -C "${srcdir}" rev-parse --is-inside-work-tree >/dev/null 2>&1], [
+  SCM_BRANCH=`$GIT -C "${srcdir}" symbolic-ref --quiet HEAD 2>/dev/null | sed 's,^refs/heads/,,'`
+  SCM_VERSION=`$GIT -C "${srcdir}" rev-parse --short=7 HEAD 2>/dev/null`
+])
+
+AC_SUBST([SCM_BRANCH])
+AC_SUBST([SCM_VERSION])
+
 AH_TOP([
 #ifndef UCX_CONFIG_H
 #define UCX_CONFIG_H
@@ -85,9 +89,44 @@ AC_FUNC_STRERROR_R
 AC_C_RESTRICT
 AC_FUNC_STRERROR_R
 
-AC_PATH_TOOL([PKG_CONFIG], [pkg-config], [pkg-config])
+PKG_PROG_PKG_CONFIG
 
+dnl Float word order can differ from integer endianness on some ABIs.
+ dnl Prefer Autoconf's macro if available; otherwise fall back to autoconf-archive.
+ m4_ifdef([AC_C_FLOAT_WORDS_BIGENDIAN],
+          [AC_C_FLOAT_WORDS_BIGENDIAN],
+          [m4_ifdef([AX_C_FLOAT_WORDS_BIGENDIAN],
+                    [AX_C_FLOAT_WORDS_BIGENDIAN],
+                    [AC_MSG_ERROR([need AC_C_FLOAT_WORDS_BIGENDIAN or AX_C_FLOAT_WORDS_BIGENDIAN])])])
 
+AC_CHECK_HEADERS([sys/eventfd.h sys/timerfd.h])
+AC_CHECK_HEADERS([netinet/in.h arpa/inet.h])
+
+AC_CHECK_FUNCS([brk sbrk])
+
+AS_IF([test "x$ac_cv_func_brk" = "xyes" && test "x$ac_cv_func_sbrk" = "xyes"],
+      [have_brk_sbrk=yes],
+      [have_brk_sbrk=no])
+
+have_ucm_malloc_hooks=no
+case "$host_os" in
+  linux*) have_ucm_malloc_hooks=yes ;;
+  *)      have_ucm_malloc_hooks=no ;;
+esac
+AM_CONDITIONAL([HAVE_UCM_MALLOC_HOOKS], [test "x$have_ucm_malloc_hooks" = xyes])
+
+AM_CONDITIONAL([HAVE_BRK_SBRK], [test "x$have_brk_sbrk" = "xyes"])
+AS_IF([test "x$have_brk_sbrk" = "xyes"],
+      [AC_DEFINE([HAVE_BRK_SBRK], [1],
+                 [Define if both brk() and sbrk() are available])],
+      [])
+
+case "$host_os" in
+  freebsd*) build_gtest=no ;;
+  *)        build_gtest=yes ;;
+esac
+AM_CONDITIONAL([BUILD_GTEST], [test "x$build_gtest" = xyes])
+
 #
 # Define SHARED_LIB preprocessor macro when building a shared library
 #
@@ -255,6 +294,22 @@ AS_IF([test "x$with_docs_only" = xyes],
      m4_include([test/apps/iodemo/configure.m4])
      m4_include([test/apps/uct_info/configure.m4])
 
+AS_IF([test "x$with_docs_only" != xyes && test "x$build_gtest" = xyes], [
+  PKG_CHECK_MODULES([GTEST], [gtest_main],
+                    [have_gtest=yes],
+                    [have_gtest=no])
+], [
+  have_gtest=no
+])
+
+AM_CONDITIONAL([HAVE_GTEST], [test "x$have_gtest" = "xyes"])
+
+GTEST_CPPFLAGS="${GTEST_CFLAGS}"
+GTEST_CXXFLAGS="${GTEST_CFLAGS}"
+GTEST_LDFLAGS=""
+AC_SUBST([GTEST_CPPFLAGS])
+AC_SUBST([GTEST_CXXFLAGS])
+AC_SUBST([GTEST_LDFLAGS])
 
      #
      # Disable checking user parameters