Add call to malloc_trim on a full GC

src/gc.c

@@ -6,6 +6,9 @@
 
 #include <string.h>
 #include <stdlib.h>
+#ifdef HAS_MALLOC_TRIM
+#include <malloc.h>
+#endif
 #include <mruby.h>
 #include <mruby/array.h>
 #include <mruby/class.h>
@@ -1319,6 +1322,9 @@ mrb_full_gc(mrb_state *mrb)
     gc->full = FALSE;
   }
 
+#ifdef HAS_MALLOC_TRIM
+  malloc_trim(0);
+#endif
   GC_TIME_STOP_AND_REPORT;
 }
 

tasks/toolchains/gcc.rake

@@ -31,6 +31,8 @@ MRuby::Toolchain.new(:gcc) do |conf, params|
   end
 
   [[conf.cc, 'c'], [conf.cxx, 'c++']].each do |cc, lang|
+    cc.defines += %w(HAS_MALLOC_TRIM) if cc.has_function? 'malloc_trim', with_header: 'malloc.h'
+
     cc.instance_variable_set :@header_search_language, lang
     def cc.header_search_paths
       if @header_search_command != command