Define both pkg-config and pkgconfig for meson

In Meson cross-files, "pkgconfig" was deprecated in favor of
"pkg-config" in meson 1.3.0.

The new name is used since 85a94dd4b563e961304b2d9082932c5c1cc2e582 to
avoid a warning, but then it fails with older versions of meson.

To avoid the problem, define both pkg-config and pkgconfig.

> For backward compatibility it is still allowed to define both with the
> same value, in that case no deprecation warning is printed.

<https://mesonbuild.com/Release-notes-for-1-3-0.html#machine-files-pkgconfig-field-deprecated-and-replaced-by-pkgconfig>

.github/workflows/release.yml

@@ -137,9 +137,6 @@ jobs:
              libavutil-dev libswresample-dev libusb-1.0-0 libusb-1.0-0-dev \
              mingw-w64 mingw-w64-tools libz-mingw-w64-dev
 
-      - name: Workaround for old meson version run by Github Actions
-        run: sed -i 's/^pkg-config/pkgconfig/' cross_win32.txt
-
       - name: Build
         run: release/build_windows.sh 32
 
@@ -171,9 +168,6 @@ jobs:
              libavutil-dev libswresample-dev libusb-1.0-0 libusb-1.0-0-dev \
              mingw-w64 mingw-w64-tools libz-mingw-w64-dev
 
-      - name: Workaround for old meson version run by Github Actions
-        run: sed -i 's/^pkg-config/pkgconfig/' cross_win64.txt
-
       - name: Build
         run: release/build_windows.sh 64
 

cross_win32.txt

@@ -7,6 +7,8 @@ cpp = 'i686-w64-mingw32-g++'
 ar = 'i686-w64-mingw32-ar'
 strip = 'i686-w64-mingw32-strip'
 pkg-config = 'i686-w64-mingw32-pkg-config'
+# backward compatibility
+pkgconfig = 'i686-w64-mingw32-pkg-config'
 windres = 'i686-w64-mingw32-windres'
 
 [host_machine]

cross_win64.txt

@@ -7,6 +7,8 @@ cpp = 'x86_64-w64-mingw32-g++'
 ar = 'x86_64-w64-mingw32-ar'
 strip = 'x86_64-w64-mingw32-strip'
 pkg-config = 'x86_64-w64-mingw32-pkg-config'
+# backward compatibility
+pkgconfig = 'x86_64-w64-mingw32-pkg-config'
 windres = 'x86_64-w64-mingw32-windres'
 
 [host_machine]