[PATCH v2] build: set rte toolchain macros from predefined macros

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

Stop writing RTE_TOOLCHAIN_XXX macros to rte_build_config.h. When an
application builds it doesn't necessarily use the same toolchain that
DPDK was built with.

Instead evaluate toolchain predefined macros and define
RTE_TOOLCHAIN_XXX macros as appropriate each time rte_config.h is
preprocessed.

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---

v2:
  * use defined(macro) to correctly test for predefined macros

 config/meson.build  |  2 --
 config/rte_config.h | 11 +++++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/config/meson.build b/config/meson.build
index a9ccd56..0c3550e 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -180,8 +180,6 @@ if not is_ms_compiler
 endif
 
 toolchain = cc.get_id()
-dpdk_conf.set_quoted('RTE_TOOLCHAIN', toolchain)
-dpdk_conf.set('RTE_TOOLCHAIN_' + toolchain.to_upper().underscorify(), 1)
 
 dpdk_conf.set('RTE_ARCH_64', cc.sizeof('void *') == 8)
 dpdk_conf.set('RTE_ARCH_32', cc.sizeof('void *') == 4)
diff --git a/config/rte_config.h b/config/rte_config.h
index da265d7..d743a5c 100644
--- a/config/rte_config.h
+++ b/config/rte_config.h
@@ -14,6 +14,17 @@
 
 #include <rte_build_config.h>
 
+#if defined(__clang__)
+#define RTE_TOOLCHAIN "clang"
+#define RTE_TOOLCHAIN_CLANG 1
+#elif defined(__GNUC__)
+#define RTE_TOOLCHAIN "gcc"
+#define RTE_TOOLCHAIN_GCC 1
+#elif defined(_MSC_VER)
+#define RTE_TOOLCHAIN "msvc"
+#define RTE_TOOLCHAIN_MSVC 1
+#endif
+
 /* legacy defines */
 #ifdef RTE_EXEC_ENV_LINUX
 #define RTE_EXEC_ENV_LINUXAPP 1
-- 
1.8.3.1