Merge #17678: depends: Support for S390X and POWER targets

11113247c3 depends: Support for S390X targets (MarcoFalke)
989fd539d5 depends: Support for 64-bit POWER targets (Luke Dashjr)

Pull request description:

  Failure before:

  ```
  $ make -C depends HOST=powerpc64-linux-gnu
  ...
  ERROR: Feature 'system-zlib' was enabled, but the pre-condition 'libs.zlib' failed.

  ERROR: Feature 'xcb' was enabled, but the pre-condition 'libs.xcb' failed.

  ERROR: Feature 'system-freetype' was enabled, but the pre-condition 'features.freetype && libs.freetype' failed.

  ERROR: Feature 'fontconfig' was enabled, but the pre-condition '!config.win32 && !config.darwin && features.system-freetype && libs.fontconfig' failed.
  make: *** [funcs.mk:254: /bitcoin/depends/work/build/powerpc64-linux-gnu/qt/5.9.8-95548079095/qtbase/.stamp_configured] Error 3

  $ make -C depends HOST=s390x-linux-gnu
  ...
  ERROR: Feature 'system-zlib' was enabled, but the pre-condition 'libs.zlib' failed.

  ERROR: Feature 'xcb' was enabled, but the pre-condition 'libs.xcb' failed.

  ERROR: Feature 'system-freetype' was enabled, but the pre-condition 'features.freetype && libs.freetype' failed.

  ERROR: Feature 'fontconfig' was enabled, but the pre-condition '!config.win32 && !config.darwin && features.system-freetype && libs.fontconfig' failed.
  make: *** [funcs.mk:254: /bitcoin/depends/work/build/s390x-linux-gnu/qt/5.9.8-79c6d6ca6ec/qtbase/.stamp_configured] Error 3
  ```

ACKs for top commit:
  laanwj:
    Code review ACK 11113247c3
  dongcarl:
    tested ACK 11113247c3
  practicalswift:
    ACK 11113247c3 -- diff looks correct

Tree-SHA512: f990101ced0ed579168bb25762c1296c9b512c597bab924013af41832670a69ed786c6ec9b654c95fe064187797880a66c575395bc102a914c1bdb323ca7538a

depends/.gitignore

@@ -8,5 +8,7 @@ i686*
 mips*
 arm*
 aarch64*
+powerpc*
 riscv32*
 riscv64*
+s390x*

depends/Makefile

@@ -191,7 +191,7 @@ $(host_prefix)/share/config.site: check-packages
 check-packages: check-sources
 
 clean-all: clean
-	@rm -rf $(SOURCES_PATH) x86_64* i686* mips* arm* aarch64* riscv32* riscv64*
+	@rm -rf $(SOURCES_PATH) x86_64* i686* mips* arm* aarch64* powerpc* riscv32* riscv64* s390x*
 
 clean:
 	@rm -rf $(WORK_PATH) $(BASE_CACHE) $(BUILD)

depends/README.md

@@ -12,13 +12,13 @@ For example:
 
     make HOST=x86_64-w64-mingw32 -j4
 
-**Bitcoin's configure script by default will ignore the depends output.** In
+**Bitcoin Core's configure script by default will ignore the depends output.** In
 order for it to pick up libraries, tools, and settings from the depends build,
 you must point it at the appropriate `--prefix` directory generated by the
 build. In the above example, a prefix dir named x86_64-w64-mingw32 will be
 created. To use it for Bitcoin:
 
-    ./configure --prefix=`pwd`/depends/x86_64-w64-mingw32
+    ./configure --prefix=$PWD/depends/x86_64-w64-mingw32
 
 Common `host-platform-triplets` for cross compilation are:
 
@@ -28,8 +28,11 @@ Common `host-platform-triplets` for cross compilation are:
 - `x86_64-apple-darwin16` for macOS
 - `arm-linux-gnueabihf` for Linux ARM 32 bit
 - `aarch64-linux-gnu` for Linux ARM 64 bit
+- `powerpc64-linux-gnu` for Linux POWER 64-bit (big endian)
+- `powerpc64le-linux-gnu` for Linux POWER 64-bit (little endian)
 - `riscv32-linux-gnu` for Linux RISC-V 32 bit
 - `riscv64-linux-gnu` for Linux RISC-V 64 bit
+- `s390x-linux-gnu` for Linux S390X
 - `armv7a-linux-android` for Android ARM 32 bit
 - `aarch64-linux-android` for Android ARM 64 bit
 - `i686-linux-android` for Android x86 32 bit
@@ -61,6 +64,10 @@ For linux AARCH64 cross compilation:
 
     sudo apt-get install g++-aarch64-linux-gnu binutils-aarch64-linux-gnu
 
+For linux POWER 64-bit cross compilation (there are no packages for 32-bit):
+
+    sudo apt-get install g++-powerpc64-linux-gnu binutils-powerpc64-linux-gnu g++-powerpc64le-linux-gnu binutils-powerpc64le-linux-gnu
+
 For linux RISC-V 64-bit cross compilation (there are no packages for 32-bit):
 
     sudo apt-get install g++-riscv64-linux-gnu binutils-riscv64-linux-gnu
@@ -68,6 +75,10 @@ For linux RISC-V 64-bit cross compilation (there are no packages for 32-bit):
 RISC-V known issue: gcc-7.3.0 and gcc-7.3.1 result in a broken `test_bitcoin` executable (see https://github.com/bitcoin/bitcoin/pull/13543),
 this is apparently fixed in gcc-8.1.0.
 
+For linux S390X cross compilation:
+
+    sudo apt-get install g++-s390x-linux-gnu binutils-s390x-linux-gnu
+
 ### Dependency Options
 The following can be set when running make: make FOO=bar
 

depends/packages/qt.mk

@@ -129,7 +129,10 @@ $(package)_config_opts_arm_linux += -platform linux-g++ -xplatform bitcoin-linux
 $(package)_config_opts_i686_linux  = -xplatform linux-g++-32
 $(package)_config_opts_x86_64_linux = -xplatform linux-g++-64
 $(package)_config_opts_aarch64_linux = -xplatform linux-aarch64-gnu-g++
+$(package)_config_opts_powerpc64_linux = -platform linux-g++ -xplatform bitcoin-linux-g++
+$(package)_config_opts_powerpc64le_linux = -platform linux-g++ -xplatform bitcoin-linux-g++
 $(package)_config_opts_riscv64_linux = -platform linux-g++ -xplatform bitcoin-linux-g++
+$(package)_config_opts_s390x_linux = -platform linux-g++ -xplatform bitcoin-linux-g++
 
 $(package)_config_opts_mingw32 = -no-opengl
 $(package)_config_opts_mingw32 += -no-dbus