Created attachment 134783 [details]
pc file used as an example

As I see Windows command line supports quotation marks only to escape spaces in a path. But pkg-config tool adds backslashes to escape spaces in a path.
Because of this it looks impossible to use pkg-config on Windows if include path or lib path contain spaces. 
Example without spaces:
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C:\tmp>for /F "delims=," %i in ('pkg-config --cflags --libs win-path-wspace-test') do cl x.c %i
C:\tmp>cl x.c -IC:\\tmp/include  C:\\tmp/libs/a.lib
Microsoft (R) C/C++ Optimizing Compiler Version 19.00.24215.1 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

x.c
Microsoft (R) Incremental Linker Version 14.00.24215.1
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:x.exe
x.obj
C:\\tmp/libs/a.lib
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Example with spaces:
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C:\tmp>for /F "delims=," %i in ('pkg-config --cflags --libs win-path-wspace-test') do cl x.c %i
C:\tmp>cl x.c -IC:\\Program\ Files\ (x86)\\tmp/include  C:\\Program\ Files\ (x86)\\tmp/libs/a.lib
Microsoft (R) C/C++ Optimizing Compiler Version 19.00.24215.1 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

cl : Command line warning D9024 : unrecognized source file type 'Files\', object file assumed
cl : Command line warning D9024 : unrecognized source file type '(x86)\\tmp/include', object file assumed
cl : Command line warning D9024 : unrecognized source file type 'C:\\Program\', object file assumed
cl : Command line warning D9024 : unrecognized source file type 'Files\', object file assumed
x.c
x.c(3): fatal error C1083: Cannot open include file: 'a.h': No such file or directory
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Could you add possibility to get quotation marks for those paths on Windows that contains spaces to escape them? So that it would be much easier to work with pkg-config on Windows.

And just nice-to-have: when I set path with spaces to PKG_CONFIG_PATH Windows command line adds quotation marks to this path automatically but path with quotation marks can not be found by pkg-config tool 
From debug output:
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C:\tmp>set PKG_CONFIG_PATH="C:\work\pkg config"
C:\tmp>pkg-config --cflags --libs --debug win-path-wspace-test
Option --debug seen
Error printing enabled by default due to use of --version, --libs, --cflags, --libs-only-l, --libs-only-L, --libs-only-other, --cflags-only-I, --cflags-only-other or --list. Value of --silence-errors: 0
Error printing enabled
Adding virtual 'pkg-config' package to list of known packages
Cannot open directory '"C:/tmp/pkg config"' in package search path: No such file or directory
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