disable werror (#191)

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ This is a development pre-release.
 - Solidity: Add the solc `--libraries` files to sources.
 - A data race in tests.
 - Fix `broken pipe` errors.
+- llvm-builder: Allow warnings.
 
 ## v0.1.0-dev.9
 

crates/llvm-builder/src/platforms/shared.rs

@@ -40,17 +40,9 @@ pub const SHARED_BUILD_OPTS_NOT_MUSL: [&str; 4] = [
 
 /// The shared build options to treat warnings as errors.
 ///
-/// Disabled on Windows due to the following upstream issue with MSYS2 with mingw-w64:
-/// ProgramTest.cpp:23:15: error: '__p__environ' redeclared without 'dllimport' attribute
-pub fn shared_build_opts_werror(target_env: TargetEnv) -> Vec<String> {
-    vec![format!(
-        "-DLLVM_ENABLE_WERROR='{}'",
-        if cfg!(target_os = "windows") || target_env == TargetEnv::Emscripten {
-            "Off"
-        } else {
-            "On"
-        },
-    )]
+/// Disabled because it makes the build very brittle.
+pub fn shared_build_opts_werror(_target_env: TargetEnv) -> Vec<String> {
+    vec!["-DLLVM_ENABLE_WERROR='Off'".to_string()]
 }
 
 /// The build options to set the default target.