Merge bitcoin#29706: depends: set two CMake options globally

76045bb depends: always set CMAKE_POSITION_INDEPENDENT_CODE=ON (fanquake)
d046236 depends: always set CMAKE_INSTALL_LIBDIR=lib/ (fanquake)

Pull request description:

  Set `CMAKE_INSTALL_LIBDIR=lib/` and `CMAKE_POSITION_INDEPENDENT_CODE=ON` globally in depends, rather than per-package. `CMAKE_INSTALL_LIBDIR=lib/` is needed to override the annoying [`GNUInstallDirs`](https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html) `lib` vs `lib64` behaviour, and we always want PIC code. The PIC commit is the counterpart to the same Autotools change in bitcoin#29488. I'm PRing these commits as I have a CMake branch building on top, and want to avoid adding the same workarounds to every package we are going to touch, but these can go in separately as the build should be tested for existing packages (i.e multiprocess).

ACKs for top commit:
  hebasto:
    re-ACK 76045bb.
  theuni:
    utACK 76045bb. Both changes make sense to me, and both can be overridden if needed, though I can't imagine we'd need to.

Tree-SHA512: 655a0b6b7ee5a5820f52e8e919ef03fc216d29f13f3904f72b64ce57436510e073c903039488d5740535c56e1f6221267229238c5231de5f8467d238fd562578

depends/funcs.mk

@@ -170,12 +170,19 @@ ifneq ($($(1)_ldflags),)
 $(1)_autoconf += LDFLAGS="$$($(1)_ldflags)"
 endif
 
+# We hardcode the library install path to "lib" to match the PKG_CONFIG_PATH
+# setting in depends/config.site.in, which also hardcodes "lib".
+# Without this setting, CMake by default would use the OS library
+# directory, which might be "lib64" or something else, not "lib", on multiarch systems.
 $(1)_cmake=env CC="$$($(1)_cc)" \
                CFLAGS="$$($(1)_cppflags) $$($(1)_cflags)" \
                CXX="$$($(1)_cxx)" \
                CXXFLAGS="$$($(1)_cppflags) $$($(1)_cxxflags)" \
                LDFLAGS="$$($(1)_ldflags)" \
-             cmake -DCMAKE_INSTALL_PREFIX:PATH="$$($($(1)_type)_prefix)" $$($(1)_config_opts)
+               cmake -DCMAKE_INSTALL_PREFIX:PATH="$$($($(1)_type)_prefix)" \
+               -DCMAKE_INSTALL_LIBDIR=lib/ \
+               -DCMAKE_POSITION_INDEPENDENT_CODE=ON \
+               $$($(1)_config_opts)
 ifeq ($($(1)_type),build)
 $(1)_cmake += -DCMAKE_INSTALL_RPATH:PATH="$$($($(1)_type)_prefix)/lib"
 else

depends/packages.md

@@ -163,7 +163,7 @@ From the [Gentoo Wiki entry](https://wiki.gentoo.org/wiki/Project:Quality_Assura
 >  ecosystem, as it leads to a massive number of unnecessary rebuilds.
 
 Where possible, packages are built with Position Independant Code. Either using
-the autotools `--with-pic` flag, or `DCMAKE_POSITION_INDEPENDENT_CODE` with CMake.
+the Autotools `--with-pic` flag, or `CMAKE_POSITION_INDEPENDENT_CODE` with CMake.
 
 ## Secondary dependencies:
 

depends/packages/capnp.mk

@@ -5,15 +5,10 @@ $(package)_download_file=$(native_$(package)_download_file)
 $(package)_file_name=$(native_$(package)_file_name)
 $(package)_sha256_hash=$(native_$(package)_sha256_hash)
 
-# Hardcode library install path to "lib" to match the PKG_CONFIG_PATH
-# setting in depends/config.site.in, which also hardcodes "lib".
-# Without this setting, cmake by default would use the OS library
-# directory, which might be "lib64" or something else, not "lib", on multiarch systems.
 define $(package)_set_vars :=
   $(package)_config_opts := -DBUILD_TESTING=OFF
   $(package)_config_opts += -DWITH_OPENSSL=OFF
   $(package)_config_opts += -DWITH_ZLIB=OFF
-  $(package)_config_opts += -DCMAKE_INSTALL_LIBDIR=lib/
 endef
 
 define $(package)_config_cmds

depends/packages/libmultiprocess.mk

@@ -8,13 +8,7 @@ ifneq ($(host),$(build))
 $(package)_dependencies += native_capnp
 endif
 
-# Hardcode library install path to "lib" to match the PKG_CONFIG_PATH
-# setting in depends/config.site.in, which also hardcodes "lib".
-# Without this setting, cmake by default would use the OS library
-# directory, which might be "lib64" or something else, not "lib", on multiarch systems.
 define $(package)_set_vars :=
-$(package)_config_opts += -DCMAKE_INSTALL_LIBDIR=lib/
-$(package)_config_opts += -DCMAKE_POSITION_INDEPENDENT_CODE=ON
 ifneq ($(host),$(build))
 $(package)_config_opts := -DCAPNP_EXECUTABLE="$$(native_capnp_prefixbin)/capnp"
 $(package)_config_opts += -DCAPNPC_CXX_EXECUTABLE="$$(native_capnp_prefixbin)/capnpc-c++"