external/breakpad: Work around -fsanitize=alignment

...as seen in the scenario described in 5997121a
"Support signal handlers registered with SA_SIGINFO", first

> src/client/linux/minidump_writer/directory_reader.h:82:19: runtime error: member access within misaligned address 0x7f3f8235c2cc for type 'struct kernel_dirent', which requires 8 byte alignment
> 0x7f3f8235c2cc: note: pointer points here
>   10 02 00 00 d8 f8 3b 00  00 00 00 00 01 00 00 00  00 00 00 00 18 00 2e 00  00 00 00 04 02 c7 3b 00

and then

> src/client/linux/minidump_writer/linux_dumper.cc:382:19: runtime error: member access within misaligned address 0x7f96c225d7bc for type 'google_breakpad::MappingInfo', which requires 8 byte alignment
> 0x7f96c225d7bc: note: pointer points here
>   20 0a 32 30 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
>               ^

Change-Id: I7f739567879093a404bee3e351ce9e8257676183

external/breakpad/UnpackedTarball_breakpad.mk

@@ -9,6 +9,8 @@
 
 $(eval $(call gb_UnpackedTarball_UnpackedTarball,breakpad))
 
+$(eval $(call gb_UnpackedTarball_set_patchlevel,breakpad,0))
+
 $(eval $(call gb_UnpackedTarball_set_tarball,breakpad,$(BREAKPAD_TARBALL)))
 
 $(eval $(call gb_UnpackedTarball_add_patches,breakpad,\
@@ -18,4 +20,12 @@ $(eval $(call gb_UnpackedTarball_add_patches,breakpad,\
 	external/breakpad/breakpad-stackwalk.patch.1 \
 ))
 
+ifeq ($(COM_IS_CLANG),TRUE)
+ifneq ($(filter -fsanitize=%,$(CC)),)
+$(eval $(call gb_UnpackedTarball_add_patches,breakpad, \
+    external/breakpad/ubsan.patch \
+))
+endif
+endif
+
 # vim: set noet sw=4 ts=4:

external/breakpad/ubsan.patch

+--- src/client/linux/minidump_writer/directory_reader.h
++++ src/client/linux/minidump_writer/directory_reader.h
+@@ -96,7 +96,7 @@
+   const int fd_;
+   bool hit_eof_;
+   unsigned buf_used_;
+-  uint8_t buf_[sizeof(struct kernel_dirent) + NAME_MAX + 1];
++  uint8_t buf_[sizeof(struct kernel_dirent) + NAME_MAX + 1] __attribute__ ((aligned (__BIGGEST_ALIGNMENT__)));
+ };
+ 
+ }  // namespace google_breakpad
+--- src/common/memory.h
++++ src/common/memory.h
+@@ -75,6 +75,7 @@
+     if (!bytes)
+       return NULL;
+ 
++    bytes = (bytes + (__BIGGEST_ALIGNMENT__ - 1)) & ~(__BIGGEST_ALIGNMENT__ - 1);
+     if (current_page_ && page_size_ - page_offset_ >= bytes) {
+       uint8_t *const ret = current_page_ + page_offset_;
+       page_offset_ += bytes;