diff --git a/CMakeLists.txt b/CMakeLists.txt
index d49508a0..25e45c16 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -397,6 +397,10 @@ int main(void) {
 }"
   HAVE_SNPRINTF)
 
+if(NOT HAVE_SNPRINTF)
+  add_definitions(-DNEED_LIBPORT)
+endif()
+
 # CPU bit order
 set(fillorder FILLORDER_MSB2LSB)
 if(CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "i.*86.*" OR
diff --git a/ChangeLog b/ChangeLog
index 41716a15..7e85a50a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-08-20  Bob Friesenhahn  <bfriesen@simple.dallas.tx.us>
+
+	* tools/CMakeLists.txt, port/snprintf.c: Patch by Roger Leigh to
+	fix build issues when using Cmake due to Windows large file
+	changes.
+
 2015-08-18  Bob Friesenhahn  <bfriesen@simple.dallas.tx.us>
 
 	* libtiff/tiffiop.h: First cut at supporting large files under
diff --git a/port/snprintf.c b/port/snprintf.c
index ce261291..1c4ac087 100644
--- a/port/snprintf.c
+++ b/port/snprintf.c
@@ -11,7 +11,7 @@
 #include <stdarg.h>
 #include "libport.h"
 
-int vsnprintf(char* str, size_t size, const char* format, va_list ap)
+int _TIFF_vsnprintf_f(char* str, size_t size, const char* format, va_list ap)
 {
   int count = -1;
 
@@ -23,7 +23,7 @@ int vsnprintf(char* str, size_t size, const char* format, va_list ap)
   return count;
 }
 
-int snprintf(char* str, size_t size, const char* format, ...)
+int _TIFF_snprintf_f(char* str, size_t size, const char* format, ...)
 {
   int count;
   va_list ap;
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index c8a5005f..a595c4b8 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -26,6 +26,7 @@ extra_dist(Makefile.vc)
 
 include_directories(${PROJECT_SOURCE_DIR}/libtiff
                     ${PROJECT_BINARY_DIR}/libtiff
+                    ${PROJECT_SOURCE_DIR}/port
                     ${CMAKE_CURRENT_BINARY_DIR})
 
 add_executable(bmp2tiff bmp2tiff.c)