Alias init functions

	The extension library has each initialization function named "Init_" +
	basename. If multiple extensions have the same base name (such as
	cgi/escape and erb/escape), the same function will be registered for
	both names.

	To fix this conflict, rename the initialization functions under sub
	directories using using parent names, when statically linking.
	---
	 ext/extmk.rb            | 16 +++++++++++++++-
	 template/extinit.c.tmpl |  2 +-
	 2 files changed, 16 insertions(+), 2 deletions(-)

	[Bug #19778] Pass additional include options to INCFLAGS in common.mk

	---
	 common.mk            | 2 +-
	 configure.ac         | 1 +
	 template/Makefile.in | 1 +
	 3 files changed, 3 insertions(+), 1 deletion(-)

	[Bug #19778] Add `-I` options for opt-dir to `$INCFLAGS`

	These options have been separated from `$CFLAGS` already in the
	other places.
	---
	 configure.ac | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

	Fix parallel build on MINGW

	When the build is running with a base ruby then generating `x64-ucrt-ruby320.rc`
	could fail due to a missing dependency to `x64-mingw-ucrt-fake.rb`.
	This commit adds this dependency.

	A failing build looks like so:
	```
	generating x64-mingw-ucrt-fake.rb
	generating x64-ucrt-ruby320.rc
	../snapshot-master/win32/resource.rb:in `require': cannot load such file -- ./x64-mingw-ucrt-fake (LoadError)
	make: *** [GNUmakefile:57: x64-ucrt-ruby320.rc] Error 1
	make: *** Waiting for unfinished jobs....
	linking miniruby.exe
	x64-mingw-ucrt-fake.rb updated
	```
	---
	 cygwin/GNUmakefile.in | 4 ++--
	 template/Makefile.in  | 1 +
	 2 files changed, 3 insertions(+), 2 deletions(-)

	Exclude LIBPATHENV wrapper from PREP

	---
	 common.mk            | 4 ++--
	 configure.ac         | 2 +-
	 template/Makefile.in | 2 ++
	 3 files changed, 5 insertions(+), 3 deletions(-)

	Move duplicate dependencies

	---
	 common.mk            | 2 ++
	 template/Makefile.in | 5 -----
	 win32/Makefile.sub   | 2 --
	 3 files changed, 2 insertions(+), 7 deletions(-)

	Run find in PATH [ci skip]

	---
	 template/Makefile.in | 2 +-
	 1 file changed, 1 insertion(+), 1 deletion(-)

	Clean intermediate files for update-deps [ci skip]

	---
	 template/Makefile.in | 1 +
	 1 file changed, 1 insertion(+)

	Load fake.rb at `BTESTRUBY`

	So that `mkmf` checks work from `make run`, and also remove
	duplicate `$(MINIRUBYOPT)` which is used in `$(MINIRUBY)`.
	---
	 common.mk            | 8 ++++----
	 template/Makefile.in | 3 +--
	 template/fake.rb.in  | 2 ++
	 win32/Makefile.sub   | 2 +-
	 4 files changed, 8 insertions(+), 7 deletions(-)