[fontconfig] build failure

[andresy]

Host Environment

• OS: Linux
• Compiler: gcc 9.3.0

To Reproduce
Steps to reproduce the behavior:

This assumes gperf is not available system-wide, but only through vcpkg.

./vcpkg install gperf
./vcpkg install fontconfig

Failure logs

Building package fontconfig[core]:x64-linux...
-- Using cached /private/home/locronan/vcpkg/downloads/fontconfig-fontconfig-844d8709a1f3ecab45015b24b72dd775c13b2421.tar.gz
-- Cleaning sources at /private/home/locronan/vcpkg/buildtrees/fontconfig/src/75c13b2421-4651fd65ce.clean. Use --editable to skip cleaning for the packages you specify.
-- Extracting source /private/home/locronan/vcpkg/downloads/fontconfig-fontconfig-844d8709a1f3ecab45015b24b72dd775c13b2421.tar.gz
-- Applying patch remove_tests.patch
-- Applying patch build.patch
-- Applying patch build2.patch
-- Applying patch disable-install-data.patch
-- Using source at /private/home/locronan/vcpkg/buildtrees/fontconfig/src/75c13b2421-4651fd65ce.clean
CMake Error at scripts/cmake/vcpkg_find_acquire_program.cmake:535 (message):
  Could not find gperf.  Please install it via your package manager.
Call Stack (most recent call first):
  ports/fontconfig/portfile.cmake:21 (vcpkg_find_acquire_program)
  scripts/ports.cmake:128 (include)


Error: Building package fontconfig:x64-linux failed with: BUILD_FAILED
Please ensure you're using the latest portfiles with `./vcpkg update`, then
submit an issue at https://github.com/Microsoft/vcpkg/issues including:
  Package: fontconfig:x64-linux
  Vcpkg version: 2021-01-13-unknownhash

Additional context

It looks like fontconfig relies on gperf (via vcpkg_find_acquire_program). When gperf is installed via vcpkg (not system install), fontconfig is unable to find gperf.

A workaround is to manually add in PATH the vcpkg gperf executable path, but I believe this should be automated.

[NancyLi1013]

Hi @andresy

Thanks for posting this issue.

Currently, ports depend on the tools in vcpkg to build via vcpkg_find_acquire_program. Since the tool gperf is only supported on Windows, you need to install it manually via apt-get install gperf on Unix platform.

But you can post these issues there #6045.

[JackBoosY]

I think we should add our tool path to head of CMAKE_PROGRAM_PATH.

@BillyONeal @ras0219 what do you think about?

[BillyONeal]

I think we should add our tool path to head of CMAKE_PROGRAM_PATH.

I believe not doing that and wanting porfile.cmakes to explicitly handle each of their dependencies is intended to discourage "accidental dependencies".

[FrankXie05]

@andresy Is still working for this issue, I didn't reproduce it locally. Make sure your vcpkg library is updated to the latest version and try again. If you still have questions, please reply to me. :)

test:~/test/vcpkg$ ./vcpkg install gperf
Computing installation plan...
The following packages will be built and installed:
    gperf[core]:x64-linux -> 3.1#3
Detecting compiler hash for triplet x64-linux...
Restored 0 packages from /home/test/.cache/vcpkg/archives in 49.47 ms. Use --debug to see more details.
Starting package 1/1: gperf:x64-linux
Building package gperf[core]:x64-linux...
-- Downloading http://ftp.gnu.org/pub/gnu/gperf/gperf-3.1.tar.gz -> gperf-3.1.tar.gz...
-- Extracting source /home/test/test/vcpkg/downloads/gperf-3.1.tar.gz
-- Using source at /home/test/test/vcpkg/buildtrees/gperf/src/gperf-3-d4135ad4b1.clean
-- Configuring x64-linux-dbg
-- Configuring x64-linux-rel
-- Building x64-linux-dbg
-- Building x64-linux-rel
-- Installing: /home/test/test/vcpkg/packages/gperf_x64-linux/share/gperf/copyright
-- Performing post-build validation
-- Performing post-build validation done
Stored binary cache: /home/test/.cache/vcpkg/archives/2a/2afbf7aba7bdf4dbdd8deaf584c8fe037a94360ada856756b0fa43d951d3f617.zip
Installing package gperf[core]:x64-linux...
Elapsed time for package gperf:x64-linux: 3.426 s

Total elapsed time: 3.889 s

test:~/test/vcpkg$ ./vcpkg install fontconfig
Computing installation plan...
The following packages will be built and installed:
    fontconfig[core]:x64-linux -> 2.13.94#5
Detecting compiler hash for triplet x64-linux...
Restored 1 packages from /home/test/.cache/vcpkg/archives in 249.4 ms. Use --debug to see more details.
Starting package 1/1: fontconfig:x64-linux
Installing package fontconfig[core]:x64-linux...
Elapsed time for package fontconfig:x64-linux: 38.88 ms

Total elapsed time: 707.3 ms

[FrankXie05]

Fixed by PR #24677