Drop CMake PCRE2 download/linking and allow statically-linked PCRE2 crate

pcre2-sys includes a vendored copy of PCRE2, which allows for
statically-linked PCRE2. Hook this up to the CMake build variable, and
remove the C++ integration for PCRE2.

CMakeLists.txt

@@ -31,6 +31,10 @@ add_definitions(-D_UNICODE=1)
 include(cmake/ConfigureChecks.cmake)
 include(cmake/gettext.cmake)
 
+# Set up PCRE2
+# This sets an environment variable that needs to be available before the Rust stanzas
+include(cmake/PCRE2.cmake)
+
 include(cmake/Rust.cmake)
 
 # Error out when linking statically, it doesn't work.
@@ -119,9 +123,6 @@ add_definitions(-DCMAKE_SOURCE_DIR="${REAL_CMAKE_SOURCE_DIR}")
 # Enable thread-safe errno on Solaris (#5611)
 add_definitions(-D_REENTRANT)
 
-# Set up PCRE2
-include(cmake/PCRE2.cmake)
-
 # Define a function to link dependencies.
 function(FISH_LINK_DEPS_AND_SIGN target)
   # Tell Cargo where our build directory is so it can find config.h.

cmake/PCRE2.cmake

@@ -1,77 +1,24 @@
-# PCRE2 needs some settings.
-set(PCRE2_WIDTH ${WCHAR_T_BITS})
-set(PCRE2_BUILD_PCRE2_8 OFF CACHE BOOL "Build 8bit PCRE2 library")
-set(PCRE2_BUILD_PCRE2_${PCRE2_WIDTH} ON CACHE BOOL "Build ${PCRE2_WIDTH}bit PCRE2 library")
-set(PCRE2_SHOW_REPORT OFF CACHE BOOL "Show the final configuration report")
-set(PCRE2_BUILD_TESTS OFF CACHE BOOL "Build tests")
-set(PCRE2_BUILD_PCRE2GREP OFF CACHE BOOL "Build pcre2grep")
-
-set(PCRE2_MIN_VERSION 10.21)
-
-# Look for a system-installed PCRE2.
-find_library(SYS_PCRE2_LIB pcre2-${PCRE2_WIDTH})
-find_path(SYS_PCRE2_INCLUDE_DIR pcre2.h)
-
 # We can either use the system-installed PCRE or our bundled version.
 # This is controlled by the cache variable FISH_USE_SYSTEM_PCRE2.
 # Here we compute the default value for that variable.
+# The actual decision is made by the Rust pcre2-sys crate, which searches for the
+# pkg-config file and uses a vendored copy if it is not available.
 if ((APPLE) AND (MAC_CODESIGN_ID))
   # On Mac, a codesigned fish will refuse to load a non-codesigned PCRE2
   # (e.g. from Homebrew) so default to bundled PCRE2.
   set(USE_SYS_PCRE2_DEFAULT OFF)
-elseif((NOT SYS_PCRE2_LIB) OR (NOT SYS_PCRE2_INCLUDE_DIR))
-  # We did not find system PCRE2, so default to bundled.
-  set(USE_SYS_PCRE2_DEFAULT OFF)
 else()
-  # Default to using the system PCRE2, which was found.
+  # Default to using the system PCRE2, if it can be found by the crate
   set(USE_SYS_PCRE2_DEFAULT ON)
 endif()
 
 set(FISH_USE_SYSTEM_PCRE2 ${USE_SYS_PCRE2_DEFAULT} CACHE BOOL
-  "Use PCRE2 from the system, instead of fetching and building it")
+  "Try to use PCRE2 from the system, instead of the pcre2-sys version")
 
 if(FISH_USE_SYSTEM_PCRE2)
-  set(PCRE2_LIB "${SYS_PCRE2_LIB}")
-  set(PCRE2_INCLUDE_DIR "${SYS_PCRE2_INCLUDE_DIR}")
-  message(STATUS "Using system PCRE2 library ${PCRE2_INCLUDE_DIR}")
+  message(STATUS "Trying to use PCRE2 from the system")
+  set(FISH_PCRE2_BUILDFLAG "")
 else()
-  include(FetchContent RESULT_VARIABLE HAVE_FetchContent)
-  if (${HAVE_FetchContent} STREQUAL "NOTFOUND")
-    message(FATAL_ERROR "Please install PCRE2 headers, or CMake >= 3.11 so I can download PCRE")
-  endif()
-  set(CMAKE_TLS_VERIFY true)
-  set(PCRE2_REPO "https://github.com/PCRE2Project/pcre2.git")
-
-  message(STATUS "Fetching and configuring PCRE2 from ${PCRE2_REPO}")
-  Set(FETCHCONTENT_QUIET FALSE)
-  FetchContent_Declare(
-    pcre2
-    GIT_REPOSITORY ${PCRE2_REPO}
-    GIT_TAG "72669190cb947f0cac1d038a8bb1820da59ef447" # tag: pcre2-10.36
-    GIT_SHALLOW ON
-    GIT_PROGRESS TRUE
-  )
-  # Don't try FetchContent_MakeAvailable, there's no way to add EXCLUDE_FROM_ALL
-  # so we end up installing all of PCRE2 including its headers, man pages, etc.
-  FetchContent_GetProperties(pcre2)
-  if (NOT pcre2_POPULATED)
-    # If GIT_WORK_TREE is set (by user or by git itself with e.g. git rebase), it
-    # will override the git directory which CMake tries to apply in FetchContent_Populate,
-    # resulting in a failed checkout.
-    # Ensure it is not set.
-    unset(ENV{GIT_WORK_TREE})
-    unset(ENV{GIT_DIR})
-    FetchContent_Populate(pcre2)
-    add_subdirectory(${pcre2_SOURCE_DIR} ${pcre2_BINARY_DIR} EXCLUDE_FROM_ALL)
-  endif()
-
-  set(PCRE2_INCLUDE_DIR ${pcre2_BINARY_DIR})
-  set(PCRE2_LIB pcre2-${PCRE2_WIDTH})
-
-  # Disable -Wunused-macros inside PCRE2, as it is noisy.
-  get_target_property(PCRE2_COMPILE_OPTIONS ${PCRE2_LIB} COMPILE_OPTIONS)
-  list(REMOVE_ITEM PCRE2_COMPILE_OPTIONS "-Wunused-macros")
-  set_property(TARGET ${PCRE2_LIB} PROPERTY COMPILE_OPTIONS ${PCRE2_COMPILE_OPTIONS})
-
+  message(STATUS "Forcing static build of PCRE2")
+  set(FISH_PCRE2_BUILDFLAG "CARGO_FEATURE_STATIC_PCRE2=1")
 endif(FISH_USE_SYSTEM_PCRE2)
-include_directories(${PCRE2_INCLUDE_DIR})

cmake/Rust.cmake

@@ -70,4 +70,5 @@ set(VARS_FOR_CARGO
     "BINDIR=${CMAKE_INSTALL_FULL_BINDIR}"
     "LOCALEDIR=${CMAKE_INSTALL_FULL_LOCALEDIR}"
     "CURSES_LIBRARY_LIST=${CURSES_LIBRARY_LIST}"
+    "${FISH_PCRE2_BUILDFLAG}"
 )