fix: Use -fPIC

[SuperH-0630]

In order for pcre2 to be linked by some dynamic libraries, the -fPIC option should be enabled.
为了pcre2能够被部分动态库链接，应启用-fPIC选项。

[jwsblokland]

Hello SuperH-0630,

Looking at your pull request, I am a bit puzzled about it. As far as I can see, the original CMakeLists.txt has all the options to build PCRE2 with -fPIC if needed. For example,

cmake -DBUILD_SHARED_LIBS=ON ...

builds a shared library of the selected components of the PCRE2 library. If you need a static version which has been build with -fPIC you need to run the following cmake command:

cmake -DBUILD_STATIC_LIBS=ON -DPCRE2_STATIC_PIC=ON ...

The latter one, I have used myself and I can without any problem create a dynamic library which makes used of static version of PCRE2 library.

[PhilipHazel]

I am not a Windows user, and I know very little about CMake; the contents of CMakeLists.txt are what people have advised over the years. As there seems to be disagreement here, I am not going do do anything with this pull request. Also, there are some strange Unicode characters in it.

[SuperH-0630]

Hello SuperH-0630,

Looking at your pull request, I am a bit puzzled about it. As far as I can see, the original CMakeLists.txt has all the options to build PCRE2 with -fPIC if needed. For example,

cmake -DBUILD_SHARED_LIBS=ON ...

builds a shared library of the selected components of the PCRE2 library. If you need a static version which has been build with -fPIC you need to run the following cmake command:

cmake -DBUILD_STATIC_LIBS=ON -DPCRE2_STATIC_PIC=ON ...

The latter one, I have used myself and I can without any problem create a dynamic library which makes used of static version of PCRE2 library.

Thank your suggestion. I misunderstood some usage.