diff --git a/mathlib/imagequant.cpp b/mathlib/imagequant.cpp
index bdba52a6..b84d2c5c 100644
--- a/mathlib/imagequant.cpp
+++ b/mathlib/imagequant.cpp
@@ -6,6 +6,7 @@
 //
 //=============================================================================//
 #include <quantize.h>
+#include <tier0/basetypes.h>
 
 #define N_EXTRAVALUES 1
 #define N_DIMENSIONS (3+N_EXTRAVALUES)
diff --git a/mathlib/quantize.cpp b/mathlib/quantize.cpp
index dbaf15f2..2c8c12e5 100644
--- a/mathlib/quantize.cpp
+++ b/mathlib/quantize.cpp
@@ -21,6 +21,8 @@
 
 #include <math.h>
 
+#include <tier0/basetypes.h>
+
 static int current_ndims;
 static struct QuantizedValue *current_root;
 static int current_ssize;