Cut down on -pthread/-lpthread proliferation

Building against libstdc++ effectively always requires -pthread anyway (as
various standard C++ headers require it, see the comment added to
solenv/gbuild/platform/unxgcc.mk), so many explicit uses of -pthread/-lpthread
can be removed.

Doing a (partial) test build on Linux with Clang -stdlib=libc++ suggests that
libc++ indeed doesn't need -pthread as libstdc++ does.

The remaining uses of -pthread/-lpthread are mostly in configure.ac for the
various BSDs (which somebody else might want to clean up now), and related to
external projects.  I tried to be careful to remove -pthread/-lpthread from
makefiles only when C++ object files are involved (so -pthread will now be
included on the link command line by default).

Change-Id: I936e082839cb9a434bd273ce5a1f187a4245dfa1
Reviewed-on: https://gerrit.libreoffice.org/71291
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

canvas/Executable_canvasdemo.mk

@@ -45,7 +45,6 @@ $(eval $(call gb_Executable_use_static_libraries,canvasdemo,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,canvasdemo,\
     -lm $(DLOPEN_LIBS) \
-    -lpthread \
     -lX11 \
 ))
 

connectivity/Library_mysqlc.mk

@@ -24,7 +24,7 @@ $(eval $(call gb_Library_set_include,mysqlc,\
 $(eval $(call gb_Library_add_libs,mysqlc,\
 	$(if $(filter-out WNT,$(OS)),$(if $(filter HAIKU MACOSX SOLARIS,$(OS)),\
 	-lz -lm,-rdynamic -lz -lcrypt -lm)) \
-	$(if $(filter LINUX,$(OS)),-lpthread -ldl,) \
+	$(if $(filter LINUX,$(OS)),-ldl,) \
 ))
 
 $(eval $(call gb_Library_use_sdk_api,mysqlc))

connectivity/Library_postgresql-sdbc-impl.mk

@@ -61,7 +61,6 @@ $(eval $(call gb_Library_add_libs,postgresql-sdbc-impl,\
 	$(if $(WITH_GSSAPI),$(GSSAPI_LIBS)) \
 	$(if $(WITH_KRB5),$(KRB5_LIBS)) \
 	$(if $(filter-out MACOSX,$(OS)),-ldl) \
-	$(if $(filter-out MACOSX,$(OS)),-lpthread) \
 ))
 
 endif

desktop/CppunitTest_desktop_app.mk

@@ -66,7 +66,6 @@ endif
 
 $(eval $(call gb_CppunitTest_add_libs,desktop_app,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 endif

desktop/CppunitTest_desktop_lokinit.mk

@@ -40,7 +40,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_CppunitTest_add_libs,desktop_lok_init,\
     -lm \
     -ldl \
-    -lpthread \
 ))
 endif
 

desktop/Library_crashreport.mk

@@ -26,7 +26,6 @@ $(eval $(call gb_Library_add_defs,crashreport,\
 $(eval $(call gb_Library_add_libs,crashreport,\
     $(if $(filter LINUX %BSD SOLARIS, $(OS)), \
         $(DLOPEN_LIBS) \
-        -lpthread \
     ) \
 ))
 

desktop/Library_sofficeapp.mk

@@ -19,7 +19,6 @@ $(eval $(call gb_Library_set_include,sofficeapp,\
 $(eval $(call gb_Library_add_libs,sofficeapp,\
     $(if $(filter LINUX %BSD SOLARIS, $(OS)), \
         $(DLOPEN_LIBS) \
-        -lpthread \
     ) \
 ))
 
@@ -135,7 +134,6 @@ $(eval $(call gb_Library_add_exception_objects,sofficeapp,\
 ifeq ($(DISABLE_GUI),TRUE)
 $(eval $(call gb_Library_add_libs,sofficeapp,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
 ))
 else
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
@@ -147,7 +145,6 @@ endif
 
 $(eval $(call gb_Library_add_libs,sofficeapp,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 endif

external/clucene/Library_clucene.mk

@@ -48,7 +48,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,clucene,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

external/pdfium/Library_pdfium.mk

@@ -572,7 +572,6 @@ ifneq (,$(filter LINUX ANDROID,$(OS)))
 $(eval $(call gb_Library_add_libs,pdfium,\
     -ldl \
     -lrt \
-    -lpthread \
 ))
 
 $(eval $(call gb_Library_use_external,pdfium,freetype))

jurt/Library_jpipe.mk

@@ -74,10 +74,6 @@ $(eval $(call gb_Library_use_system_darwin_frameworks,jpipe, \
 ))
 endif
 
-$(eval $(call gb_Library_add_libs,jpipe, \
-    $(if $(filter-out $(OS),ANDROID),-lpthread) \
-))
-
 $(call gb_LinkTarget_get_target,$(call gb_Library_get_linktarget,jpipe)): \
     gb_CC := $(filter-out -fsanitize%,$(gb_CC))
 $(call gb_LinkTarget_get_target,$(call gb_Library_get_linktarget,jpipe)): \

libreofficekit/CppunitTest_libreofficekit_tiledrendering.mk

@@ -28,7 +28,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_CppunitTest_add_libs,libreofficekit_tiledrendering,\
     -lm \
     -ldl \
-    -lpthread \
 ))
 endif
 

libreofficekit/Executable_gtktiledviewer.mk

@@ -43,7 +43,6 @@ $(eval $(call gb_Executable_use_libraries,gtktiledviewer,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,gtktiledviewer,\
     -lm $(DLOPEN_LIBS) \
-    -lpthread \
 ))
 endif
 

libreofficekit/Executable_tilebench.mk

@@ -24,7 +24,6 @@ $(eval $(call gb_Executable_use_libraries,tilebench,\
 
 $(eval $(call gb_Executable_add_libs,tilebench,\
     -lm $(DLOPEN_LIBS) \
-    -lpthread \
 ))
 
 $(eval $(call gb_Executable_add_exception_objects,tilebench,\

onlineupdate/Executable_test_updater_dialog.mk

@@ -57,7 +57,6 @@ $(eval $(call gb_Executable_add_libs,test_updater_dialog,\
 	-lXrender \
 	-lSM \
 	-lICE \
-	-lpthread \
 ))
 endif
 

onlineupdate/Executable_updater.mk

@@ -70,7 +70,6 @@ $(eval $(call gb_Executable_add_libs,updater,\
 	-lXrender \
 	-lSM \
 	-lICE \
-	-lpthread \
 ))
 endif
 

sal/Library_sal.mk

@@ -56,9 +56,6 @@ $(eval $(call gb_Library_use_system_win32_libs,sal,\
 ))
 
 $(eval $(call gb_Library_add_libs,sal,\
-	$(if $(filter-out ANDROID HAIKU WNT,$(OS)), \
-		-lpthread \
-	) \
 	$(if $(filter LINUX,$(OS)), \
 		-ldl \
 		-lrt \

sc/CppunitTest_sc_ucalc.mk

@@ -118,12 +118,6 @@ $(eval $(call gb_CppunitTest_add_libs,sc_ucalc,\
 ))
 endif
 
-ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
-$(eval $(call gb_CppunitTest_add_libs,sc_ucalc,\
-    -lpthread \
-))
-endif
-
 $(eval $(call gb_CppunitTest_use_configuration,sc_ucalc))
 
 # vim: set noet sw=4 ts=4:

sc/Library_sc.mk

@@ -718,12 +718,6 @@ $(eval $(call gb_Library_add_libs,sc,\
 ))
 endif
 
-ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
-$(eval $(call gb_Library_add_libs,sc,\
-    -lpthread \
-))
-endif
-
 $(eval $(call gb_SdiTarget_SdiTarget,sc/sdi/scslots,sc/sdi/scalc))
 
 $(eval $(call gb_SdiTarget_set_include,sc/sdi/scslots,\

smoketest/Executable_libtest.mk

@@ -16,7 +16,6 @@ $(eval $(call gb_Executable_set_include,libtest,\
 ifeq ($(OS),LINUX)
 $(eval $(call gb_Executable_add_libs,libtest,\
 	-ldl \
-	-pthread \
 ))
 endif
 

solenv/gbuild/platform/linux.mk

@@ -18,7 +18,7 @@ gb_LinkTarget_LDFLAGS += $(gb__LinkTarget_LDFLAGS_zdefs)
 include $(GBUILDDIR)/platform/unxgcc.mk
 
 ifeq ($(DISABLE_DYNLOADING),TRUE)
-gb_STDLIBS := -lpthread -ldl
+gb_STDLIBS := -ldl
 endif
 
 # vim: set noet sw=4 ts=4:

solenv/gbuild/platform/unxgcc.mk

@@ -42,12 +42,20 @@ gb_CFLAGS := \
 	-Wdeclaration-after-statement \
 	-Wshadow \
 
+# At least libstdc++ (which is approximated here with !HAVE_LIBCXX) needs -pthread when including
+# various C++ headers like <thread>, see <https://gcc.gnu.org/onlinedocs/gcc-8.3.0/libstdc++/manual/
+# manual/using.html#manual.intro.using.flags>:
+ifeq ($(HAVE_LIBCXX),)
+gb_CXX_LINKFLAGS := -pthread
+endif
+
 gb_CXXFLAGS := \
 	$(gb_CXXFLAGS_COMMON) \
 	-fPIC \
 	-Wshadow \
 	-Woverloaded-virtual \
 	$(CXXFLAGS_CXX11) \
+	$(gb_CXX_LINKFLAGS) \
 
 
 # enable debug STL
@@ -112,7 +120,7 @@ gb_LinkTarget_CXXFLAGS := $(gb_CXXFLAGS)
 # contains .c sources:
 define gb_LinkTarget__command_dynamiclink
 $(call gb_Helper_abbreviate_dirs,\
-	$(if $(CXXOBJECTS)$(GENCXXOBJECTS)$(EXTRAOBJECTLISTS)$(filter-out XTRUE,X$(ENABLE_RUNTIME_OPTIMIZATIONS)),$(gb_CXX),$(gb_CC)) \
+	$(if $(CXXOBJECTS)$(GENCXXOBJECTS)$(EXTRAOBJECTLISTS)$(filter-out XTRUE,X$(ENABLE_RUNTIME_OPTIMIZATIONS)),$(gb_CXX) $(gb_CXX_LINKFLAGS),$(gb_CC)) \
 		$(if $(filter Library CppunitTest,$(TARGETTYPE)),$(gb_Library_TARGETTYPEFLAGS)) \
 		$(gb_LTOFLAGS) \
 		$(if $(SOVERSIONSCRIPT),-Wl$(COMMA)--soname=$(notdir $(1)) \

svl/Library_svl.mk

@@ -111,11 +111,6 @@ $(eval $(call gb_Library_use_externals,svl,\
     nss3 \
     plc4 \
 ))
-ifeq ($(OS),LINUX)
-$(eval $(call gb_Library_add_libs,svl, \
-    -lpthread \
-))
-endif
 endif # BUILD_TYPE=DESKTOP
 endif
 

svx/Executable_gengal.mk

@@ -64,13 +64,11 @@ endif
 ifeq ($(DISABLE_GUI),TRUE)
 $(eval $(call gb_Executable_add_libs,gengal,\
 	$(DLOPEN_LIBS) \
-	-lpthread \
 ))
 else
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,gengal,\
 	$(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Executable_icontest.mk

@@ -37,7 +37,6 @@ $(eval $(call gb_Executable_use_static_libraries,icontest,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,icontest,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Executable_lo_kde5filepicker.mk

@@ -92,7 +92,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Executable_add_libs,lo_kde5filepicker,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Executable_mtfdemo.mk

@@ -43,7 +43,6 @@ $(eval $(call gb_Executable_use_static_libraries,mtfdemo,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,mtfdemo,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Executable_ui-previewer.mk

@@ -37,7 +37,6 @@ $(eval $(call gb_Executable_add_exception_objects,ui-previewer,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,ui-previewer,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Executable_vcldemo.mk

@@ -53,7 +53,6 @@ $(eval $(call gb_Executable_use_static_libraries,vcldemo,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Executable_add_libs,vcldemo,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Executable_visualbackendtest.mk

@@ -45,7 +45,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Executable_add_libs,visualbackendtest,\
 	-lm \
 	-ldl \
-	-lpthread \
     -lX11 \
 ))
 

vcl/Library_desktop_detector.mk

@@ -66,7 +66,6 @@ $(eval $(call gb_Library_add_exception_objects,desktop_detector,\
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Library_add_libs,desktop_detector,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
 ))
 endif
 

vcl/Library_vcl.mk

@@ -545,11 +545,6 @@ $(eval $(call gb_Library_use_externals,vcl,\
     freetype \
     fontconfig \
 ))
-ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
-$(eval $(call gb_Library_add_libs,vcl,\
-    -lpthread \
-))
-endif
 
 else # ! DISABLE_GUI
 
@@ -578,7 +573,6 @@ endif
 ifeq ($(OS), $(filter LINUX %BSD SOLARIS, $(OS)))
 $(eval $(call gb_Library_add_libs,vcl,\
     -lm $(DLOPEN_LIBS) \
-    -lpthread \
     -lX11 \
     -lXext \
 ))

vcl/Library_vclplug_gen.mk

@@ -145,7 +145,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_gen,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Library_vclplug_gtk.mk

@@ -126,7 +126,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_gtk,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Library_vclplug_gtk3.mk

@@ -116,7 +116,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_gtk3,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Library_vclplug_gtk3_kde5.mk

@@ -124,7 +124,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_gtk3_kde5,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Library_vclplug_kde5.mk

@@ -89,7 +89,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_kde5,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/Library_vclplug_qt5.mk

@@ -114,7 +114,6 @@ ifeq ($(OS),LINUX)
 $(eval $(call gb_Library_add_libs,vclplug_qt5,\
 	-lm \
 	-ldl \
-	-lpthread \
 ))
 endif
 

vcl/StaticLibrary_glxtest.mk

@@ -31,7 +31,6 @@ $(eval $(call gb_StaticLibrary_use_api,glxtest,\
 
 $(eval $(call gb_StaticLibrary_add_libs,glxtest,\
 	-lm $(DLOPEN_LIBS) \
-	-lpthread \
     -lX11 \
 ))