[rollup] 2021-07-26 (#19157)

* [rollup:2021-07-26 1/6] PR #18783 (@strega-nil)

[scripts-audit] vcpkg_copy_tools and friends

* [rollup:2021-07-26 2/6] PR #18898 (@dg0yt)

[vcpkg] Fix toolchain compatibility with cmake < 3.15

* [rollup:2021-07-26 3/6] PR #18980 (@strega-nil)

[cmake-guidelines] Minor update, for `if()`

* [rollup:2021-07-26 4/6] PR #18981 (@strega-nil)

[scripts-audit] vcpkg_check_linkage

* [rollup:2021-07-26 5/6] PR #19158 (@Hoikas)

[vcpkg.cmake] Fix variable case.

* [rollup:2021-07-26 6/6] PR #18839

[scripts-audit] z_vcpkg_get_cmake_vars

Co-authored-by: nicole mazzuca <mazzucan@outlook.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/docs/maintainers/ports/vcpkg-cmake/vcpkg_cmake_get_vars.md b/docs/maintainers/ports/vcpkg-cmake/vcpkg_cmake_get_vars.md
new file mode 100644
index 000000000..68e51333c
--- /dev/null
+++ b/docs/maintainers/ports/vcpkg-cmake/vcpkg_cmake_get_vars.md
@@ -0,0 +1,31 @@
+# vcpkg_cmake_get_vars
+
+The latest version of this document lives in the [vcpkg repo](https://github.com/Microsoft/vcpkg/blob/master/docs/maintainers/ports/vcpkg-cmake/vcpkg_cmake_get_vars.md).
+
+Runs a cmake configure with a dummy project to extract certain cmake variables
+
+## Usage
+```cmake
+vcpkg_cmake_get_vars(<out-var>)
+```
+
+`vcpkg_cmake_get_vars(<out-var>)` sets `<out-var>` to
+a path to a generated CMake file, with the detected `CMAKE_*` variables
+re-exported as `VCPKG_DETECTED_CMAKE_*`.
+
+## Notes
+Avoid usage in portfiles.
+
+All calls to `vcpkg_cmake_get_vars` will result in the same output file;
+the output file is not generated multiple times.
+
+### Basic Usage
+
+```cmake
+vcpkg_cmake_get_vars(cmake_vars_file)
+include("${cmake_vars_file}")
+message(STATUS "detected CXX flags: ${VCPKG_DETECTED_CMAKE_CXX_FLAGS}")
+```
+
+## Source
+[ports/vcpkg-cmake/vcpkg\_cmake\_get\_vars.cmake](https://github.com/Microsoft/vcpkg/blob/master/ports/vcpkg-cmake/vcpkg_cmake_get_vars.cmake)