Error needed/conflicts configuration

The purpose is to clarify the error if there is a needed/conflicts
configuration at compile time.

mrbgems/mruby-bin-debugger/tools/mrdb/mrdbconf.h

@@ -6,6 +6,10 @@
 #ifndef MRDBCONF_H
 #define MRDBCONF_H
 
+#ifndef MRB_ENABLE_DEBUG_HOOK
+# error Need 'MRB_ENABLE_DEBUG_HOOK' configuration in your 'build_config.rb'
+#endif
+
 /* configuration options: */
 /* maximum size for command buffer */
 #define MAX_COMMAND_LINE 1024

mrbgems/mruby-math/src/math.c

@@ -4,6 +4,10 @@
 ** See Copyright Notice in mruby.h
 */
 
+#ifdef MRB_WITHOUT_FLOAT
+# error Conflict 'MRB_WITHOUT_FLOAT' configuration in your 'build_config.rb'
+#endif
+
 #include <mruby.h>
 #include <mruby/array.h>
 

mrbgems/mruby-random/src/random.c

@@ -4,6 +4,10 @@
 ** See Copyright Notice in mruby.h
 */
 
+#ifdef MRB_WITHOUT_FLOAT
+# error Conflict 'MRB_WITHOUT_FLOAT' configuration in your 'build_config.rb'
+#endif
+
 #include <mruby.h>
 #include <mruby/variable.h>
 #include <mruby/class.h>

mrbgems/mruby-range-ext/src/range.c

@@ -1,3 +1,7 @@
+#ifdef MRB_WITHOUT_FLOAT
+# error Conflict 'MRB_WITHOUT_FLOAT' configuration in your 'build_config.rb'
+#endif
+
 #include <mruby.h>
 #include <mruby/range.h>
 #include <math.h>

mrbgems/mruby-time/src/time.c

@@ -4,6 +4,10 @@
 ** See Copyright Notice in mruby.h
 */
 
+#ifdef MRB_WITHOUT_FLOAT
+# error Conflict 'MRB_WITHOUT_FLOAT' configuration in your 'build_config.rb'
+#endif
+
 #include <math.h>
 #include <time.h>
 #include <mruby.h>