[Meson] HarfBuzz fails to build with enabled support for ICU

[Arfrever]

Since commit daab4bf, HarfBuzz fails to build with enabled support for ICU (-Dicu=enabled passed to meson) if ICU's .pc files specify multiple elements in value of DEFS variable.

meson setup --libdir lib64 --localstatedir /var/lib --prefix /usr --sysconfdir /etc --wrap-mode nodownload --build.pkg-config-path /var/tmp/portage/media-libs/harfbuzz-3.4.0/temp/python3.10/pkgconfig:/usr/share/pkgconfig --pkg-config-path /var/tmp/portage/media-libs/harfbuzz-3.4.0/temp/python3.10/pkgconfig:/usr/share/pkgconfig --native-file /var/tmp/portage/media-libs/harfbuzz-3.4.0/temp/meson.x86_64-pc-linux-gnu.amd64.ini --buildtype plain -Dcoretext=disabled -Dchafa=disabled -Dglib=enabled -Dgraphite2=enabled -Dicu=enabled -Dgobject=enabled -Dtests=disabled -Dfreetype=enabled -Dcairo=enabled -Ddocs=disabled -Dintrospection=enabled -Dexperimental_api=false /var/tmp/portage/media-libs/harfbuzz-3.4.0/work/harfbuzz-3.4.0 /var/tmp/portage/media-libs/harfbuzz-3.4.0/work/harfbuzz-3.4.0-abi_x86_64.amd64
...
Run-time dependency icu-uc found: YES 70.1
...

meson compile -C /var/tmp/portage/media-libs/harfbuzz-3.4.0/work/harfbuzz-3.4.0-abi_x86_64.amd64 --jobs 1 --load-average 0 --verbose
...
[68/86] x86_64-pc-linux-gnu-g++ -Isrc/libharfbuzz-icu.so.0.30400.0.p -Isrc -I../harfbuzz-3.4.0/src -I. -I../harfbuzz-3.4.0 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wnon-virtual-dtor -std=c++11 -fno-rtti -fno-exceptions -fno-rtti -fno-threadsafe-statics -fvisibility-inlines-hidden '-DU_DISABLE_RENAMING=1 -DUCONFIG_ENABLE_PLUGINS=1' -DHAVE_CONFIG_H -march=native -O2 -fno-ident -frecord-gcc-switches -fstack-clash-protection -fstack-protector-all -mfunction-return=thunk -mindirect-branch=thunk -mindirect-branch-register -pipe -Wall -Werror=terminate -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_CONCEPT_CHECKS -std=c++14 -DHB_NDEBUG -fPIC -Wno-non-virtual-dtor -MD -MQ src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o -MF src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o.d -o src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o -c ../harfbuzz-3.4.0/src/hb-icu.cc
FAILED: src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o 
x86_64-pc-linux-gnu-g++ -Isrc/libharfbuzz-icu.so.0.30400.0.p -Isrc -I../harfbuzz-3.4.0/src -I. -I../harfbuzz-3.4.0 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wnon-virtual-dtor -std=c++11 -fno-rtti -fno-exceptions -fno-rtti -fno-threadsafe-statics -fvisibility-inlines-hidden '-DU_DISABLE_RENAMING=1 -DUCONFIG_ENABLE_PLUGINS=1' -DHAVE_CONFIG_H -march=native -O2 -fno-ident -frecord-gcc-switches -fstack-clash-protection -fstack-protector-all -mfunction-return=thunk -mindirect-branch=thunk -mindirect-branch-register -pipe -Wall -Werror=terminate -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_CONCEPT_CHECKS -std=c++14 -DHB_NDEBUG -fPIC -Wno-non-virtual-dtor -MD -MQ src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o -MF src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o.d -o src/libharfbuzz-icu.so.0.30400.0.p/hb-icu.cc.o -c ../harfbuzz-3.4.0/src/hb-icu.cc
<command-line>: error: token "=" is not valid in preprocessor expressions
<command-line>: error: token "=" is not valid in preprocessor expressions
ninja: build stopped: subcommand failed.

As seen above, '-DU_DISABLE_RENAMING=1 -DUCONFIG_ENABLE_PLUGINS=1' (in single quotes) was passed to compiler.
Since it was in single quotes, it was treated as single argument, not multiple separate arguments.

In meson-log.txt:

...
Called `/usr/bin/pkg-config --variable=DEFS icu-uc` -> 0
-DU_DISABLE_RENAMING=1 -DUCONFIG_ENABLE_PLUGINS=1
Got pkgconfig variable DEFS : -DU_DISABLE_RENAMING=1 -DUCONFIG_ENABLE_PLUGINS=1
...

Fix working for me:

--- meson.build
+++ meson.build
@@ -130,8 +130,8 @@
 endif
 
 if icu_dep.found() and icu_dep.type_name() == 'pkgconfig'
-  icu_defs = icu_dep.get_variable(pkgconfig: 'DEFS', default_value: '')
-  if icu_defs != ''
+  icu_defs = icu_dep.get_variable(pkgconfig: 'DEFS', default_value: '').split()
+  if icu_defs.length() > 0
     add_project_arguments(icu_defs, language: ['c', 'cpp'])
   endif
 endif

[jameshilliard]

I made a pull request with your suggested patch in #3459.