Fall back to /etc/os-release when lsb_release is unavailable

lsb_release is absent on CentOS Stream 9 and Fedora 44+ by default.
Parse /etc/os-release as a fallback — it is present on all systemd-based
distros. Capitalize the ID field to match lsb_release output so existing
Ubuntu/Debian codename checks downstream continue to work unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: bas524

CMakeLists.txt

@@ -20,21 +20,45 @@ configure_file(${CMAKE_SOURCE_DIR}/resources/qldd.desktop.in ${CMAKE_BINARY_DIR}
 
 function(get_linux_lsb_release_information)
     find_program(LSB_RELEASE_EXEC lsb_release)
-    if(NOT LSB_RELEASE_EXEC)
-        message(WARNING "lsb_release not found; distro info will be unavailable")
+    if(LSB_RELEASE_EXEC)
+        execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --id OUTPUT_VARIABLE LSB_RELEASE_ID_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
+        execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --release OUTPUT_VARIABLE LSB_RELEASE_VERSION_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
+        execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --codename OUTPUT_VARIABLE LSB_RELEASE_CODENAME_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
+        set(LSB_RELEASE_ID_SHORT "${LSB_RELEASE_ID_SHORT}" PARENT_SCOPE)
+        set(LSB_RELEASE_VERSION_SHORT "${LSB_RELEASE_VERSION_SHORT}" PARENT_SCOPE)
+        set(LSB_RELEASE_CODENAME_SHORT "${LSB_RELEASE_CODENAME_SHORT}" PARENT_SCOPE)
+    elseif(EXISTS "/etc/os-release")
+        # Fallback: parse /etc/os-release (present on all systemd-based distros)
+        set(_id "unknown")
+        set(_version "unknown")
+        set(_codename "unknown")
+        file(STRINGS "/etc/os-release" _os_release)
+        foreach(_line ${_os_release})
+            if(_line MATCHES "^ID=(.+)$")
+                set(_id "${CMAKE_MATCH_1}")
+                string(REPLACE "\"" "" _id "${_id}")
+                # Capitalize first letter to match lsb_release output (ubuntu -> Ubuntu)
+                string(SUBSTRING "${_id}" 0 1 _first)
+                string(TOUPPER "${_first}" _first)
+                string(SUBSTRING "${_id}" 1 -1 _rest)
+                set(_id "${_first}${_rest}")
+            elseif(_line MATCHES "^VERSION_ID=(.+)$")
+                set(_version "${CMAKE_MATCH_1}")
+                string(REPLACE "\"" "" _version "${_version}")
+            elseif(_line MATCHES "^VERSION_CODENAME=(.+)$")
+                set(_codename "${CMAKE_MATCH_1}")
+                string(REPLACE "\"" "" _codename "${_codename}")
+            endif()
+        endforeach()
+        set(LSB_RELEASE_ID_SHORT "${_id}" PARENT_SCOPE)
+        set(LSB_RELEASE_VERSION_SHORT "${_version}" PARENT_SCOPE)
+        set(LSB_RELEASE_CODENAME_SHORT "${_codename}" PARENT_SCOPE)
+    else()
+        message(WARNING "Neither lsb_release nor /etc/os-release found; distro info unavailable")
         set(LSB_RELEASE_ID_SHORT "unknown" PARENT_SCOPE)
         set(LSB_RELEASE_VERSION_SHORT "unknown" PARENT_SCOPE)
         set(LSB_RELEASE_CODENAME_SHORT "unknown" PARENT_SCOPE)
-        return()
     endif()
-
-    execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --id OUTPUT_VARIABLE LSB_RELEASE_ID_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
-    execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --release OUTPUT_VARIABLE LSB_RELEASE_VERSION_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
-    execute_process(COMMAND "${LSB_RELEASE_EXEC}" --short --codename OUTPUT_VARIABLE LSB_RELEASE_CODENAME_SHORT OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-    set(LSB_RELEASE_ID_SHORT "${LSB_RELEASE_ID_SHORT}" PARENT_SCOPE)
-    set(LSB_RELEASE_VERSION_SHORT "${LSB_RELEASE_VERSION_SHORT}" PARENT_SCOPE)
-    set(LSB_RELEASE_CODENAME_SHORT "${LSB_RELEASE_CODENAME_SHORT}" PARENT_SCOPE)
 endfunction()
 
 message(STATUS "COMMITTER_FULLSHA ${COMMITTER_FULLSHA}")