Commit 91292b1 for zlib

commit 91292b1c442ae0f960badf17a9bdfd071b7b0c7b
Author: Marcin Serwin <marcin@serwin.dev>
Date:   Wed Feb 18 18:20:57 2026 +0100

    CMake: Emit correct variables for absolute install directories.

    The CMAKE_INSTALL_*DIR variables can be absolute. In that case they
    should not be appended to the prefix.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index eef01a8..22a49e4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,6 +112,16 @@ check_c_source_compiles(

 unset(CMAKE_COMPILE_FLAGS)
 set(ZLIB_PC ${zlib_BINARY_DIR}/zlib.pc)
+if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+    set(pc_includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+    set(pc_includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
+if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+    set(pc_libdir "${CMAKE_INSTALL_LIBDIR}")
+else()
+    set(pc_libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+endif()
 configure_file(${zlib_SOURCE_DIR}/zlib.pc.cmakein ${ZLIB_PC} @ONLY)
 configure_file(${zlib_BINARY_DIR}/zconf.h.cmakein ${zlib_BINARY_DIR}/zconf.h)

diff --git a/zlib.pc.cmakein b/zlib.pc.cmakein
index 6f19473..c8edaf6 100644
--- a/zlib.pc.cmakein
+++ b/zlib.pc.cmakein
@@ -1,8 +1,8 @@
 prefix=@CMAKE_INSTALL_PREFIX@
 exec_prefix=${prefix}
-libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
-sharedlibdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
-includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+libdir=@pc_libdir@
+sharedlibdir=${libdir}
+includedir=@pc_includedir@

 Name: zlib
 Description: zlib compression library