Describe the bug
When ICU is built for Windows (MSVC) target with debug variant, its configure script adds -lm library to Libs.private property of pkgconfig files. As as I know, this library does not exist in MSVC toolchain. It is not used with dynamic linking, but static linking with pkgconfig results in linking error.

Environment

• OS: Windows
• Compiler: MSVC 19.29.30138

To Reproduce
Steps to reproduce the behavior:

1. ./vcpkg install icu:x64-windows-static pkgconf:x64-windows-static
2. Try to link to static ICU library by using pkgconfig
3. Try to build CMake project with following CMakeLists.txt: https://gist.github.com/equeim/851df8e69165e509d9a511d1071e5631,
   dummy main.cpp and following CMake configuration command:

cmake -S \path\to\source -B \path\to\build -GNinja -DCMAKE_TOOLCHAIN_FILE=\path\to\vcpkg\scripts\buildsystems\vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows-static -DPKG_CONFIG_EXECUTABLE=\path\to\vcpkg\installed\x64-windows-static\tools\pkgconf\pkgconf.exe -DCMAKE_BUILD_TYPE=Debug

2. Observe linking error LINK : fatal error LNK1104: cannot open file 'm.lib'

Expected behavior
Statically linking ICU using pkgconfig should work.

Failure logs
build.log

Additional context
I believe that passing ac_cv_lib_m_floor=no to configure script in icu/portfile.cmake for MSVC toolchain fixes the issue but I don't know whether it is the correct solution.