From d203ad2b7a6970bdb8e3a802da4259f52f4f0492 Mon Sep 17 00:00:00 2001
From: fanquake <fanquake@gmail.com>
Date: Mon, 8 Jul 2024 14:59:43 +0100
Subject: [PATCH] problem: using `-errwarn` on non-Sun systems

solution: only use `-errwarn` on SunPro systems

For example, using Clang on Alpine, this just results in build spam, and
the option is incorrectly passed through to ld, which trys to use use it
(`-e`) as an entrypoint, i.e:
```bash
[ 28%] Building CXX object CMakeFiles/local_lat.dir/perf/local_lat.cpp.o
clang++: warning: -e rrwarn=%all: 'linker' input unused [-Wunused-command-line-argument]
[ 29%] Linking CXX executable bin/local_lat
/usr/bin/ld: warning: cannot find entry symbol rrwarn=%all; defaulting to 0000000000000cf0
[ 29%] Built target local_lat
```
---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 18594938..b16bdb80 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -705,7 +705,7 @@ if(LIBZMQ_WERROR)
     zmq_check_cxx_flag_prepend("/WX")
   else()
     zmq_check_cxx_flag_prepend("-Werror")
-    if(NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    if(${CMAKE_CXX_COMPILER_ID} MATCHES "SunPro")
       zmq_check_cxx_flag_prepend("-errwarn=%all")
     endif()
   endif()