Try to address #1761 -- failures of makeotfexe in the manylinux wheel

.github/workflows/build_wheels.yml

@@ -62,7 +62,7 @@ jobs:
         # CIBW_BEFORE_ALL_LINUX: "yum install -y libuuid-devel"
         # CIBW_BEFORE_ALL_LINUX: "dnf -y install uuid-devel"
         CIBW_ENVIRONMENT_MACOS: "CFLAGS='-I/usr/include/libxml2' MACOSX_DEPLOYMENT_TARGET='10.13'"
-        CIBW_ENVIRONMENT_LINUX: "FORCE_BUILD_LIBXML2=ON"
+        CIBW_ENVIRONMENT_LINUX: "FORCE_BUILD_LIBXML2=ON PTHREAD_STATIC_WORKAROUND=1"
         CIBW_ENVIRONMENT_WINDOWS: "FORCE_BUILD_LIBXML2=ON"
 
     - name: Build sdist (Ubuntu only)

CMakeLists.txt

@@ -42,6 +42,9 @@ set(ANTLR4_WITH_STATIC_CRT OFF)
 set(ANTLR4_TAG tags/4.13.2)
 include(ExternalAntlr4Cpp)
 
+if (DEFINED ENV{PTHREAD_STATIC_WORKAROUND})
+    set(PTHREAD_STATIC_WORKAROUND TRUE)
+endif()
 
 if (DEFINED ENV{FORCE_BUILD_LIBXML2})
     set(BUILD_STATIC_LIBXML2 TRUE)

c/makeotf/source/CMakeLists.txt

@@ -31,6 +31,11 @@ target_link_libraries(makeotfexe PUBLIC ${CHOSEN_LIBXML2_LIBRARY})
 
 target_compile_definitions(makeotfexe PRIVATE MAKEOTFLIB_EXPORTS=1)
 
+if (PTHREAD_STATIC_WORKAROUND)
+    target_compile_definitions(makeotfexe PRIVATE PTHREAD_STATIC_WORKAROUND=1)
+endif ()
+
+
 # set_target_properties(makeotfexe PROPERTIES MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
 
 install(TARGETS makeotfexe DESTINATION bin)

c/makeotf/source/main.cpp

@@ -1,5 +1,13 @@
 extern "C" int c_main(int argc, char *argv[]);
 
+#ifdef PTHREAD_STATIC_WORKAROUND
+#include <pthread.h>
+#endif
+
 int main(int argc, char *argv[]) {
+#ifdef PTHREAD_STATIC_WORKAROUND
+    static_cast<void>(pthread_create);
+    static_cast<void>(pthread_cancel);
+#endif
     c_main(argc, argv);
 }