Install.win32: Add path for pkg-config

INSTALL.win32

@@ -124,6 +124,7 @@ If you are cross-compiling from Debian, you can use something
 along those lines:
 
   ./bootstrap && \
+  PKG_CONFIG_LIBDIR=/usr/win32/lib/pkgconfig \
   CPPFLAGS="-I/usr/win32/include -I/usr/win32/include/ebml" \
   LDFLAGS=-L/usr/win32/lib \
   CC=i586-mingw32msvc-gcc CXX=i586-mingw32msvc-g++ \
@@ -148,6 +149,7 @@ along those lines:
 
   ./bootstrap && \
   PATH=/usr/local/mingw/bin:$PATH \
+  PKG_CONFIG_LIBDIR=/usr/win32/lib/pkgconfig \
   CPPFLAGS=-I/usr/win32/include \
   LDFLAGS=-L/usr/win32/lib \
   CC=i586-mingw32msvc-gcc CXX=i586-mingw32msvc-g++ \
@@ -173,6 +175,7 @@ hasn't been tested in about a year or so. So to build without the
 emulation layer, use something like this:
 
   ./bootstrap && \
+  PKG_CONFIG_PATH=/usr/win32/lib/pkgconfig \
   CPPFLAGS="-I/usr/win32/include -I/usr/win32/include/ebml" \
   LDFLAGS=-L/usr/win32/lib \
   CC="gcc -mno-cygwin" CXX="g++ -mno-cygwin" \
@@ -198,6 +201,7 @@ CXX="g++ -mno-cygwin" line. You're on your own though.
 If you are compiling with MSYS/MINGW, then you can use something along those
 lines:
   ./bootstrap && \
+  PKG_CONFIG_PATH=/usr/win32/lib/pkgconfig \
   CPPFLAGS="-I/usr/win32/include -I/usr/win32/include/ebml" \
   LDFLAGS=-L/usr/win32/lib \
   ./configure \