cmake: do not echo most inherited `LDFLAGS` to config files

Sync with autotools and filter out most linker flags inherited via
`CMAKE_SHARED_LINKER_FLAGS` (that includes `LDFLAGS` env) before
echoing them in `libcurl.pc` `Libs.private` and `curl-config`
`--static-libs`.

Keep inheriting `-l`, `-L`, `-F`, `--library-path=`, `-framework`
options.

Follow-up to e244d50064a56723c2ba4f0df8c847d6b70de0cb #15550
Follow-up to 9f56bb608ecfbb8978c6cb72a04d9e8b23162d82 #14681
Follow-up to 8ed66f98a954cfce92f770adeb2320deb1ea700e

Closes #15617

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 52aa1177c6c484da5f11c7bcb3bd1976e1c15a55..b0da32131ae41d209219a65f881cfca9e4f927a2 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2071,6 +2071,27 @@ if(NOT CURL_DISABLE_INSTALL)
   set(_ldflags "")
   set(LIBCURL_PC_LIBS_PRIVATE "")
 
+  # Filter CMAKE_SHARED_LINKER_FLAGS for libs and libpaths
+  string(STRIP "${CMAKE_SHARED_LINKER_FLAGS}" _custom_ldflags)
+  string(REGEX REPLACE " +-([^ \\t;]*)" ";-\\1" _custom_ldflags "${_custom_ldflags}")
+
+  set(_custom_libs "")
+  set(_custom_libdirs "")
+  foreach(_flag IN LISTS _custom_ldflags)
+    if(_flag MATCHES "^-l")
+      string(REGEX REPLACE "^-l" "" _flag "${_flag}")
+      list(APPEND _custom_libs "${_flag}")
+    elseif(_flag MATCHES "^-framework|^-F")
+      list(APPEND _custom_libs "${_flag}")
+    elseif(_flag MATCHES "^-L")
+      string(REGEX REPLACE "^-L" "" _flag "${_flag}")
+      list(APPEND _custom_libdirs "${_flag}")
+    elseif(_flag MATCHES "^--library-path=")
+      string(REGEX REPLACE "^--library-path=" "" _flag "${_flag}")
+      list(APPEND _custom_libdirs "${_flag}")
+    endif()
+  endforeach()
+
   # Avoid getting unnecessary -L options for known system directories.
   unset(_sys_libdirs)
   foreach(_libdir IN LISTS CMAKE_SYSTEM_PREFIX_PATH)
@@ -2090,7 +2111,7 @@ if(NOT CURL_DISABLE_INSTALL)
     endif()
   endforeach()
 
-  foreach(_libdir IN LISTS CURL_LIBDIRS)
+  foreach(_libdir IN LISTS _custom_libdirs CURL_LIBDIRS)
     list(FIND _sys_libdirs "${_libdir}" _libdir_index)
     if(_libdir_index LESS 0)
       list(APPEND _ldflags "-L${_libdir}")
@@ -2102,7 +2123,7 @@ if(NOT CURL_DISABLE_INSTALL)
     set(_implicit_libs ${CMAKE_C_IMPLICIT_LINK_LIBRARIES})
   endif()
 
-  foreach(_lib IN LISTS _implicit_libs CURL_LIBS)
+  foreach(_lib IN LISTS _implicit_libs _custom_libs CURL_LIBS)
     if(TARGET "${_lib}")
       set(_libname "${_lib}")
       get_target_property(_imported "${_libname}" IMPORTED)
@@ -2145,12 +2166,13 @@ if(NOT CURL_DISABLE_INSTALL)
   if(LIBCURL_PC_LIBS_PRIVATE)
     string(REPLACE ";" " " LIBCURL_PC_LIBS_PRIVATE "${LIBCURL_PC_LIBS_PRIVATE}")
   endif()
-  set(LIBCURL_PC_LDFLAGS_PRIVATE "${CMAKE_SHARED_LINKER_FLAGS}")
   if(_ldflags)
     list(REMOVE_DUPLICATES _ldflags)
     string(REPLACE ";" " " _ldflags "${_ldflags}")
-    set(LIBCURL_PC_LDFLAGS_PRIVATE "${LIBCURL_PC_LDFLAGS_PRIVATE} ${_ldflags}")
+    set(LIBCURL_PC_LDFLAGS_PRIVATE "${_ldflags}")
     string(STRIP "${LIBCURL_PC_LDFLAGS_PRIVATE}" LIBCURL_PC_LDFLAGS_PRIVATE)
+  else()
+    set(LIBCURL_PC_LDFLAGS_PRIVATE "")
   endif()
   set(LIBCURL_PC_CFLAGS_PRIVATE "-DCURL_STATICLIB")