commit 8615731637a116f7b9299c6122a0e058d43a4f6d
Author: Dominique Leuenberger <dimstar@opensuse.org>
Date:   Tue Dec 19 13:28:29 2023 +0100

    cmake: Ensure git exists before executing it
    
    CMake 3.28 has turned stricter when executing string(REPLACE …) and
    expects four or more commands. In case of distro package builds from
    tarball, it happens that git is not present. CTags.cmake tries to
    catch that by veriying the exit status of the command, but as there
    is in fact git | awk, awk returns 0 even when git does not exist.
    
    Ensure that the variable submodules has been defined before trying
    to replace substrings in this variable.
    
    Signed-off-by: Dominique Leuenberger <dimstar@opensuse.org>

diff --git a/cmake/modules/CTags.cmake b/cmake/modules/CTags.cmake
index c3e1b3799b0..772f647f947 100644
--- a/cmake/modules/CTags.cmake
+++ b/cmake/modules/CTags.cmake
@@ -3,13 +3,14 @@ find_program(CTAGS_EXECUTABLE ctags)
 function(add_tags name)
   cmake_parse_arguments(TAGS "" "SRC_DIR;TAG_FILE" "EXCLUDE_OPTS;EXCLUDES" ${ARGN})
   set(excludes ${TAGS_EXCLUDES})
+  find_package(Git)
   if(TAGS_EXCLUDE_OPTS)
     # always respect EXCLUDES_OPTS
     list(APPEND excludes ${TAGS_EXCLUDE_OPTS})
-  else()
+  elseif(Git_FOUND)
     # exclude the submodules under SRC_DIR by default
     execute_process(
-      COMMAND git config --file .gitmodules --get-regexp path
+      COMMAND ${GIT_EXECUTABLE} config --file .gitmodules --get-regexp path
       COMMAND awk "/${TAGS_SRC_DIR}/ { print $2 }"
       WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
       RESULT_VARIABLE result_code