From 32d80e91e75a68ef0c5b1ac705c3eaa6c4956fd9 Mon Sep 17 00:00:00 2001
From: T <3098462+part22@users.noreply.github.com>
Date: Fri, 18 Jun 2021 07:52:34 -0400
Subject: [PATCH] Add support to cross-compile with clang (#389)

Clang does not define __WCHAR_MIN__ however, limits.h relies on it.
By using the __AVR__ macro we can define __WCHAR_MIN__ only when
cross-compiling with clang.
---
 include/etl/limits.h                      | 5 +++++
 include/etl/profiles/determine_compiler.h | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/include/etl/limits.h b/include/etl/limits.h
index 9fa86fff..47b10a22 100644
--- a/include/etl/limits.h
+++ b/include/etl/limits.h
@@ -332,6 +332,11 @@ namespace etl
     static ETL_CONSTANT bool is_signed = etl::is_signed<wchar_t>::value;
     static ETL_CONSTANT bool is_modulo = etl::is_unsigned<wchar_t>::value;
 
+#if defined(ETL_COMPILER_CLANG) && defined(CROSS_COMPILING_TO_AVR)
+#undef WCHAR_MIN
+#define WCHAR_MIN (-WCHAR_MAX - 1)
+#endif
+
     static ETL_CONSTEXPR wchar_t min() { return WCHAR_MIN; }
     static ETL_CONSTEXPR wchar_t max() { return WCHAR_MAX; }
     static ETL_CONSTEXPR wchar_t lowest() { return WCHAR_MIN; }
diff --git a/include/etl/profiles/determine_compiler.h b/include/etl/profiles/determine_compiler.h
index b1078588..60f33c61 100644
--- a/include/etl/profiles/determine_compiler.h
+++ b/include/etl/profiles/determine_compiler.h
@@ -75,6 +75,9 @@ SOFTWARE.
     #if defined(__clang__) || defined(__llvm__)
       #define ETL_COMPILER_CLANG
       #define ETL_COMPILER_TYPE_DETECTED
+      #if __AVR__ == 1
+        #define CROSS_COMPILING_TO_AVR
+      #endif
     #endif
   #endif