diff --git a/src/base/build.mak b/src/base/build.mak
index 24351741..3e386512 100644
--- a/src/base/build.mak
+++ b/src/base/build.mak
@@ -27,10 +27,10 @@ FIXUP    = psp-fixup-imports
 ENC		 = PrxEncrypter
 
 # Add PSPSDK includes and libraries.
-INCDIR   := $(INCDIR) . $(PSPDEV)/psp/include $(PSPSDK)/include
+INCDIR   := $(INCDIR) . $(PSPSDK)/include
 LIBDIR   := $(LIBDIR) . $(PSPDEV)/psp/lib $(PSPSDK)/lib
 
-CFLAGS   := $(addprefix -I,$(INCDIR)) $(CFLAGS)
+CFLAGS   := -isystem $(PSPDEV)/psp/include $(addprefix -I,$(INCDIR)) $(CFLAGS)
 CXXFLAGS := $(CFLAGS) $(CXXFLAGS)
 ASFLAGS  := $(CFLAGS) $(ASFLAGS)
 
diff --git a/src/base/pspdev.cmake b/src/base/pspdev.cmake
index af3452f8..de74da76 100644
--- a/src/base/pspdev.cmake
+++ b/src/base/pspdev.cmake
@@ -9,7 +9,7 @@ SET(CMAKE_SYSTEM_VERSION 1)
 SET(CMAKE_SYSTEM_PROCESSOR mips)
 SET(CMAKE_C_COMPILER psp-gcc)
 SET(CMAKE_CXX_COMPILER psp-g++)
-SET(CMAKE_C_FLAGS_INIT "-I${PSPDEV}/psp/include -I${PSPDEV}/psp/sdk/include -DPSP")
+SET(CMAKE_C_FLAGS_INIT "-isystem ${PSPDEV}/psp/include -I${PSPDEV}/psp/sdk/include -DPSP")
 SET(CMAKE_CXX_FLAGS_INIT "-I${PSPDEV}/psp/include -I${PSPDEV}/psp/sdk/include -DPSP")
 SET(CMAKE_EXE_LINKER_FLAGS_INIT "-L${PSPDEV}/lib -L${PSPDEV}/psp/lib -L${PSPDEV}/psp/sdk/lib -Wl,-zmax-page-size=128")
 #SET(CMAKE_SHARED_LINKER_FLAGS_INIT "...")