bug#47964: webkitgtk-2.32.0 build fails

[Bone Baboon]

On an x86_64 computer when I run `sudo guix system --no-substitutes
reconfigure config.scm` webkitgtk-2.32.0 fails to build.  When I run
`guix build --no-substitutes --cores=1 --max-jobs=1 webkitgtk` I get
this error message:

```
make: *** [Makefile:155: all] Error 2
command "make" "-j" "1" failed with status 2
builder for `/gnu/store/b1vs7n6dvmsrk9510q8hqjnq6m9mvrm3-webkitgtk-2.32.0.drv' 
failed with exit code 1
build of /gnu/store/b1vs7n6dvmsrk9510q8hqjnq6m9mvrm3-webkitgtk-2.32.0.drv failed
View build log at 
'/var/log/guix/drvs/b1/vs7n6dvmsrk9510q8hqjnq6m9mvrm3-webkitgtk-2.32.0.drv.bz2'.
guix build: error: build of 
`/gnu/store/b1vs7n6dvmsrk9510q8hqjnq6m9mvrm3-webkitgtk-2.32.0.drv' failed
```

`guix describe` outputs:

```
Generation 7    Apr 21 2021 15:56:57    (current)
  guix ae5128e
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: ae5128e21eb7afa66bd7cfd7fd1bc5764d00663e
```

End of the build log is below.  The entire build log was too large to
send by email.

```
[ 98%] Built target gtkdoc
make -f Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/build.make 
Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/depend
make[2]: Entering directory '/tmp/guix-build-webkitgtk-2.32.0.drv-0/build'
cd /tmp/guix-build-webkitgtk-2.32.0.drv-0/build && 
/gnu/store/3dsl2jalrcyldkrsqab1hc6sv8pyag9z-cmake-minimal-3.16.5/bin/cmake -E 
cmake_depends "Unix Makefiles" 
/tmp/guix-build-webkitgtk-2.32.0.drv-0/webkitgtk-2.32.0 
/tmp/guix-build-webkitgtk-2.32.0.drv-0/webkitgtk-2.32.0/Source/WebKit 
/tmp/guix-build-webkitgtk-2.32.0.drv-0/build 
/tmp/guix-build-webkitgtk-2.32.0.drv-0/build/Source/WebKit 
/tmp/guix-build-webkitgtk-2.32.0.drv-0/build/Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/DependInfo.cmake
 --color=
Scanning dependencies of target WebKit2WebExtension-4-gir
make[2]: Leaving directory '/tmp/guix-build-webkitgtk-2.32.0.drv-0/build'
make -f Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/build.make 
Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/build
make[2]: Entering directory '/tmp/guix-build-webkitgtk-2.32.0.drv-0/build'
make[2]: *** No rule to make target 'JavaScriptCore-4.0.gir', needed by 
'WebKit2-4.0.gir'.  Stop.
make[2]: Leaving directory '/tmp/guix-build-webkitgtk-2.32.0.drv-0/build'
make[1]: *** [CMakeFiles/Makefile2:1628: 
Source/WebKit/CMakeFiles/WebKit2WebExtension-4-gir.dir/all] Error 2
make[1]: Leaving directory '/tmp/guix-build-webkitgtk-2.32.0.drv-0/build'
make: *** [Makefile:155: all] Error 2
command "make" "-j" "1" failed with status 2
```