Remove unneeded and unused patch for libmv

extern/libmv/patches/mingw_w64_support.patch

@@ -1,58 +0,0 @@
-Index: bundle.sh
-===================================================================
---- bundle.sh	(revision 45912)
-+++ bundle.sh	(working copy)
-@@ -248,7 +248,7 @@
- incs += ' ' + env['BF_PNG_INC']
- incs += ' ' + env['BF_ZLIB_INC']
- 
--if env['OURPLATFORM'] in ('win32-vc', 'win32-mingw', 'linuxcross', 'win64-vc'):
-+if env['OURPLATFORM'] in ('win32-vc', 'win32-mingw', 'linuxcross', 'win64-vc', 'win64-mingw'):
-     incs += ' ./third_party/glog/src/windows ./third_party/glog/src/windows/glog'
-     if env['OURPLATFORM'] in ('win32-vc', 'win64-vc'):
-         incs += ' ./third_party/msinttypes'
-Index: libmv/numeric/numeric.h
-===================================================================
---- libmv/numeric/numeric.h	(revision 45912)
-+++ libmv/numeric/numeric.h	(working copy)
-@@ -33,7 +33,7 @@
- #include <Eigen/QR>
- #include <Eigen/SVD>
- 
--#if _WIN32 || __APPLE__ || __FreeBSD__
-+#if (defined(_WIN32) || defined(__APPLE__) || defined(__FreeBSD__)) && !defined(__MINGW64__)
-   void static sincos (double x, double *sinx, double *cosx) {
-     *sinx = sin(x);
-     *cosx = cos(x);
-Index: third_party/glog/src/windows/port.cc
-===================================================================
---- third_party/glog/src/windows/port.cc	(revision 45912)
-+++ third_party/glog/src/windows/port.cc	(working copy)
-@@ -55,6 +55,8 @@
-   return _vsnprintf(str, size-1, format, ap);
- }
- 
-+// MinGW64 defines
-+#ifndef __MINGW64__
- int snprintf(char *str, size_t size, const char *format, ...) {
-   va_list ap;
-   va_start(ap, format);
-@@ -62,3 +64,4 @@
-   va_end(ap);
-   return r;
- }
-+#endif
-Index: third_party/glog/src/windows/port.h
-===================================================================
---- third_party/glog/src/windows/port.h	(revision 45912)
-+++ third_party/glog/src/windows/port.h	(working copy)
-@@ -120,7 +120,9 @@
- #define DEFAULT_TEMPLATE_ROOTDIR  ".."
- 
- // ----------------------------------- SYSTEM/PROCESS
-+#ifndef __MINGW64__
- typedef int pid_t;
-+#endif
- #define getpid  _getpid
- 
- // ----------------------------------- THREADS