diff --git a/aegisub/build/aegisub_vs2008/aegisub_vs2008.vcproj b/aegisub/build/aegisub_vs2008/aegisub_vs2008.vcproj
index 3b47f0a3f..4eeb99e36 100644
--- a/aegisub/build/aegisub_vs2008/aegisub_vs2008.vcproj
+++ b/aegisub/build/aegisub_vs2008/aegisub_vs2008.vcproj
@@ -810,6 +810,8 @@
 					<Tool
 						Name="VCCLCompilerTool"
 						UsePrecompiledHeader="0"
+						PrecompiledHeaderThrough=""
+						ForcedIncludeFiles="$(NOINHERIT)"
 					/>
 				</FileConfiguration>
 				<FileConfiguration
@@ -850,6 +852,8 @@
 					<Tool
 						Name="VCCLCompilerTool"
 						UsePrecompiledHeader="0"
+						PrecompiledHeaderThrough=""
+						ForcedIncludeFiles="$(NOINHERIT)"
 					/>
 				</FileConfiguration>
 				<FileConfiguration
diff --git a/aegisub/src/agi_pre.h b/aegisub/src/agi_pre.h
index bd3778c93..ade575dcf 100644
--- a/aegisub/src/agi_pre.h
+++ b/aegisub/src/agi_pre.h
@@ -40,9 +40,6 @@
 /// @note Make sure that you disable use of precompiled headers on md5.c and
 ///       MatroskaParser.c, as well as any possible future .c files.
 
-// C++ only
-#ifdef __cplusplus
-
 #include "config.h"
 
 /////////
@@ -245,8 +242,6 @@
 #include "gl/glext.h"
 #endif
 
-#ifdef _CRT_SECURE_NO_WARNINGS_DEFINED
+#ifndef _CRT_SECURE_NO_WARNINGS_DEFINED
 #undef _CRT_SECURE_NO_WARNINGS
 #endif
-
-#endif // C++