Install gbc.exe to tools/

This at least allows people to write their own codegen rules until Bond
includes its own.

ports/bond/0003_rename_gbc_during_install.patch

@@ -0,0 +1,22 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 0d743da4..72d62c5e 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -49,7 +49,14 @@ install (EXPORT bond
+ 
+ # if BOND_GBC_PATH is set we must copy over that gbc to the install location
+ if (BOND_GBC_PATH)
+-    install (FILES
+-        ${BOND_GBC_PATH}
+-        DESTINATION bin)
++  if (WIN32)
++    set(INSTALLED_GBC_NAME gbc.exe)
++  else()
++    set(INSTALLED_GBC_NAME gbc)
++  endif()
++
++  install (
++    FILES ${BOND_GBC_PATH}
++    DESTINATION bin
++    RENAME ${INSTALLED_GBC_NAME})
+ endif()

ports/bond/portfile.cmake

@@ -36,6 +36,9 @@ vcpkg_apply_patches(
     # Don't install rapidjson from the (empty) submodule. With vcpkg, we get
     # rapidjson from vcpkg
     ${CMAKE_CURRENT_LIST_DIR}/0002_omit_rapidjson.patch
+    # Temporary until this is committed upstream. See
+    # https://github.com/Microsoft/bond/pull/324 for details.
+    ${CMAKE_CURRENT_LIST_DIR}/0003_rename_gbc_during_install.patch
 )
 
 vcpkg_configure_cmake(
@@ -51,6 +54,9 @@ vcpkg_install_cmake()
 file(COPY ${SOURCE_PATH}/LICENSE DESTINATION ${CURRENT_PACKAGES_DIR}/share/bond)
 file(RENAME ${CURRENT_PACKAGES_DIR}/share/bond/LICENSE ${CURRENT_PACKAGES_DIR}/share/bond/copyright)
 
+# Drop a copy of gbc in tools/ so that it can be used
+file(COPY ${CURRENT_PACKAGES_DIR}/bin/gbc.exe DESTINATION ${CURRENT_PACKAGES_DIR}/tools/)
+
 # vcpkg doesn't--as of version 0.0.30--like executables such as gbc.exe in
 # the output. Just delete the bin/ directories for now.
 file(REMOVE_RECURSE