[vcpkg/scripts] Add a way to get cmake compiler settings/flags

[Neumann-A]

Testing the extraction of compiler settings from cmake

[Neumann-A]

CMake does not set these flags. I just took them from a default UWP VS project.

[strega-nil]

Just some minor copy changes :)

[Neumann-A]

draft until run against #9966
works good locally.

[Neumann-A]

@ras0219: about spaces. I literally tried hours to make it work. Even if you get it to through configure for some ports it is very likely that other ports requiring an external tool/script is not handling spaces in paths correctly and the build fails (even using \ , "", '', everything together or Linux itself). As such I don't bother testing with whitespaces anymore.

vcpkg/scripts/cmake/vcpkg_configure_make.cmake

Lines 218 to 221 in 70f380e

	if(CURRENT_PACKAGES_DIR MATCHES " " OR CURRENT_INSTALLED_DIR MATCHES " ")
	# Don't bother with whitespace. The tools will probably fail and I tried very hard trying to make it work (no success so far)!
	message(WARNING "Detected whitespace in root directory. Please move the path to one without whitespaces! The required tools do not handle whitespaces correctly and the build will most likely fail")
	endif()

Furthermore there are currently not that many make based ports for windows so testing is a bit difficult due to a high probability that the port is also using vcpkg_fixup_pkgconfig. So unless #13126 is finally merged I will not add an explicit test for it (If it is merged x264 could be used).

Since the compiler flags will always be a plain string and no list in cmake it is not required to change the script for meson since the flags need to be rearranged into a python list anyway which could be done in vcpkg_configure_meson. (For which I also already have an PR but we probably want to update meson first or wait until 0.56 since they now allow to pass a cmake toolchain for their find_dep stuff.)

[Neumann-A]

@ras0219 The problem is setting LDFLAGS. If the -L<somepath> has a space autotools configure chokes because the configure check passes the path with spaces as separate parameters no matter the case. I mean we could try removing the setting of -L flags in LDFLAGS and just rely on compiler specific env flags but i also think that pkgconfig might break configure for pkg_search since it is adding -L flags.

vcpkg/scripts/cmake/vcpkg_configure_make.cmake

Line 488 in b7056e9

string(REGEX REPLACE "[ \t]+/" " -" LDFLAGS_${_VAR_SUFFIX} "-L${_VCPKG_INSTALLED}${PATH_SUFFIX_${_VAR_SUFFIX}}/lib ${LD_FLAGS_GLOBAL} ${VCPKG_LINKER_FLAGS_${_VAR_SUFFIX}}")

So how should I proceed with this PR?

[JackBoosY]

Done?

[Neumann-A]

@JackBoosY: Theoretically yes. There is nothing I can do to make spaces in paths work since after the last change configure is successful but the install step fails on paths with spaces.

[JackBoosY]

@strega-nil Ping for review this PR again and merge it.