Compile C files by C compiler when C++ files mixed.

ref #3267 #3470

By this commit, mruby do not use C++ ABI mode unless
you specify explicitly. It compiles C files by C
compilers, with C++ exception enabled when it sees
C++ files in your configured mrbgems.

I haven't tried visualcpp, so please submit an issue
if you see any problem with C++ gems on Windows.

2 files changed, 4 insertions, 0 deletions

diff --git a/tasks/toolchains/gcc.rake b/tasks/toolchains/gcc.rake
index 59ae015ac..f370c0abf 100644
--- a/tasks/toolchains/gcc.rake
+++ b/tasks/toolchains/gcc.rake
@@ -7,6 +7,7 @@ MRuby::Toolchain.new(:gcc) do |conf, _params|
     cc.option_define = '-D%s'
     cc.compile_options = '%{flags} -MMD -o %{outfile} -c %{infile}'
     cc.cxx_compile_flag = '-x c++ -std=c++03'
+    cc.cxx_exception_flag = '-fexceptions'
   end
 
   [conf.cxx].each do |cxx|
@@ -17,6 +18,7 @@ MRuby::Toolchain.new(:gcc) do |conf, _params|
     cxx.option_define = '-D%s'
     cxx.compile_options = '%{flags} -MMD -o %{outfile} -c %{infile}'
     cxx.cxx_compile_flag = '-x c++ -std=c++03'
+    cxx.cxx_exception_flag = '-fexceptions'
   end
 
   conf.linker do |linker|
diff --git a/tasks/toolchains/visualcpp.rake b/tasks/toolchains/visualcpp.rake
index 5f5bab9c2..5bc24a73a 100644
--- a/tasks/toolchains/visualcpp.rake
+++ b/tasks/toolchains/visualcpp.rake
@@ -8,6 +8,7 @@ MRuby::Toolchain.new(:visualcpp) do |conf, _params|
     cc.option_define = '/D%s'
     cc.compile_options = "%{flags} /Fo%{outfile} %{infile}"
     cc.cxx_compile_flag = '/TP'
+    cc.cxx_exception_flag = '/EHs'
   end
 
   conf.cxx do |cxx|
@@ -18,6 +19,7 @@ MRuby::Toolchain.new(:visualcpp) do |conf, _params|
     cxx.option_define = '/D%s'
     cxx.compile_options = "%{flags} /Fo%{outfile} %{infile}"
     cxx.cxx_compile_flag = '/TP'
+    cxx.cxx_exception_flag = '/EHs'
   end
 
   conf.linker do |linker|