treewide: internally avoid deprecated machine file uses of "pkgconfig"

We support this in a machine file:

```
[binaries]
pkgconfig = 'pkg-config'
pkg-config = 'pkg-config'
```

and you can use either one, because internally we look up both. If you
only set *one* of them, this plays awkwardly with setting $PKG_CONFIG,
since we don't know which one you set in the machine file and the
*other* one will be initialized from the environment instead.

In commit 22df45a31981874310a78dde0df59a6a7c5ebb29 we changed program
lookup of config-tool style dependencies to use the regular tool names
and only fall back on the strange internal names. This affected the
pkg-config class too.

The result is that instead of preferring `pkgconfig =` followed by
$PKG_CONFIG followed by `pkg-config =`, we inverted the lookup order.
This is a good idea anyway, because now it behaves consistently with
`find_program('pkg-config')`.

Unfortunately, we documented the wrong name in a bunch of places, and
also used the wrong name in various testsuite bits, which meant that if
you set $PKG_CONFIG and then ran the testsuite, it would fail.

Correct these references, because they are buggy.

One test case expected to find_program() a native copy for convenience
of testing against natively installed glib. Force it to resolve a native
copy.

5 files changed, 5 insertions, 5 deletions

diff --git a/cross/armclang-linux.txt b/cross/armclang-linux.txt
index 863b355..36927b8 100644
--- a/cross/armclang-linux.txt
+++ b/cross/armclang-linux.txt
@@ -22,7 +22,7 @@ c = ['/opt/arm/developmentstudio-2019.0/sw/ARMCompiler6.12/bin/armclang', '--tar
 #cpp = '/usr/bin/arm-linux-gnueabihf-g++'
 ar = '/opt/arm/developmentstudio-2019.0/sw/ARMCompiler6.12/bin/armar'
 #strip = '/usr/arm-linux-gnueabihf/bin/strip'
-#pkgconfig = '/usr/bin/arm-linux-gnueabihf-pkg-config'
+#pkg-config = '/usr/bin/arm-linux-gnueabihf-pkg-config'
 
 [host_machine]
 system = 'baremetal'
diff --git a/cross/linux-mingw-w64-32bit.txt b/cross/linux-mingw-w64-32bit.txt
index caf1da1..91ad9c5 100644
--- a/cross/linux-mingw-w64-32bit.txt
+++ b/cross/linux-mingw-w64-32bit.txt
@@ -4,7 +4,7 @@ cpp = '/usr/bin/i686-w64-mingw32-g++'
 objc = '/usr/bin/i686-w64-mingw32-gcc'
 ar = '/usr/bin/i686-w64-mingw32-ar'
 strip = '/usr/bin/i686-w64-mingw32-strip'
-pkgconfig = '/usr/bin/i686-w64-mingw32-pkg-config'
+pkg-config = '/usr/bin/i686-w64-mingw32-pkg-config'
 windres = '/usr/bin/i686-w64-mingw32-windres'
 exe_wrapper = 'wine'
 ld = '/usr/bin/i686-w64-mingw32-ld'
diff --git a/cross/linux-mingw-w64-64bit.txt b/cross/linux-mingw-w64-64bit.txt
index 7403803..08fa704 100644
--- a/cross/linux-mingw-w64-64bit.txt
+++ b/cross/linux-mingw-w64-64bit.txt
@@ -4,7 +4,7 @@ cpp = '/usr/bin/x86_64-w64-mingw32-g++'
 objc = '/usr/bin/x86_64-w64-mingw32-gcc'
 ar = '/usr/bin/x86_64-w64-mingw32-ar'
 strip = '/usr/bin/x86_64-w64-mingw32-strip'
-pkgconfig = '/usr/bin/x86_64-w64-mingw32-pkg-config'
+pkg-config = '/usr/bin/x86_64-w64-mingw32-pkg-config'
 windres = '/usr/bin/x86_64-w64-mingw32-windres'
 exe_wrapper = 'wine'
 cmake = '/usr/bin/cmake'
diff --git a/cross/none.txt b/cross/none.txt
index 1fbe471..9eadf97 100644
--- a/cross/none.txt
+++ b/cross/none.txt
@@ -15,5 +15,5 @@ fc = ['false']
 objc = ['false']
 objcpp = ['false']
 ar = ['false']
-pkgconfig = ['false']
+pkg-config = ['false']
 cmake = ['false']
diff --git a/cross/ubuntu-armhf.txt b/cross/ubuntu-armhf.txt
index 408c2ce..6409e39 100644
--- a/cross/ubuntu-armhf.txt
+++ b/cross/ubuntu-armhf.txt
@@ -6,7 +6,7 @@ cpp = ['/usr/bin/arm-linux-gnueabihf-g++']
 rust = ['rustc', '--target', 'arm-unknown-linux-gnueabihf', '-C', 'linker=/usr/bin/arm-linux-gnueabihf-gcc-7']
 ar = '/usr/arm-linux-gnueabihf/bin/ar'
 strip = '/usr/arm-linux-gnueabihf/bin/strip'
-pkgconfig = '/usr/bin/arm-linux-gnueabihf-pkg-config'
+pkg-config = '/usr/bin/arm-linux-gnueabihf-pkg-config'
 ld = '/usr/bin/arm-linux/gnueabihf-ld'
 
 [built-in options]