From 506d03127a8565442b028ec991e1578124fd3025 Mon Sep 17 00:00:00 2001
From: Jia Tan <jiat0218@gmail.com>
Date: Fri, 29 Sep 2023 19:58:44 +0800
Subject: [PATCH] CMake: Specify LINKER_LANGUAGE for libgnu target to fix Ninja
 Generator.

CMake is unable to guess the linker language for just a header file so
it must be explicitly set.
---
 CMakeLists.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ffb381b4..3e536a87 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1008,6 +1008,12 @@ add_library(libgnu OBJECT)
 # file. So we give it a header file that results in no output files.
 target_sources(libgnu PRIVATE lib/getopt.in.h)
 
+# The Ninja Generator requires setting the linker language since it cannot
+# guess the programming language of just a header file. Setting this
+# property avoids needing an empty .c file or an non-empty unnecessary .c
+# file.
+set_target_properties(libgnu PROPERTIES LINKER_LANGUAGE C)
+
 # Create /lib directory in the build directory and add it to the include path.
 file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/lib")
 target_include_directories(libgnu PUBLIC "${CMAKE_CURRENT_BINARY_DIR}/lib")