--- /dev/null
+From 6ed0c9e58b11680779c571996a3007bd972e0853 Mon Sep 17 00:00:00 2001
+Date: Thu, 4 Aug 2022 22:52:47 +0200
+Subject: [PATCH] added emscripten support (#846)
+
+[Retrieved from:
+https://github.com/google/glog/commit/6ed0c9e58b11680779c571996a3007bd972e0853,
+to fix build without threads, a fix that is lost in the middle of a
+larger commit adding emscripten support.]
+---
+ .github/workflows/emscripten.yml | 60 ++++++++++++++++++++++++++++++++
+ CMakeLists.txt | 14 ++++----
+ src/config.h.cmake.in | 6 ++--
+ src/glog/logging.h.in | 6 ++--
+ src/glog/platform.h | 2 ++
+ src/logging.cc | 11 ++++--
+ src/raw_logging.cc | 9 ++---
+ src/stacktrace_unwind-inl.h | 2 +-
+ src/symbolize.cc | 2 +-
+ src/utilities.h | 2 +-
+ 10 files changed, 93 insertions(+), 21 deletions(-)
+ create mode 100644 .github/workflows/emscripten.yml
+
+diff --git a/.github/workflows/emscripten.yml b/.github/workflows/emscripten.yml
+new file mode 100644
+index 00000000..566c67eb
+--- /dev/null
++++ b/.github/workflows/emscripten.yml
+@@ -0,0 +1,60 @@
++name: Emscripten
++
++on: [push, pull_request]
++
++jobs:
++ build-linux:
++ defaults:
++ run:
++ shell: bash
++ name: Emscripten-C++${{matrix.std}}-${{matrix.build_type}}-${{matrix.lib}}-${{matrix.extra}}
++ runs-on: ubuntu-latest
++ container: emscripten/emsdk
++ strategy:
++ fail-fast: true
++ matrix:
++ build_type: [Release, Debug]
++ extra: [no-custom-prefix, custom-prefix]
++ lib: [static]
++ std: [98, 11, 14, 17, 20]
++
++ steps:
++ - uses: actions/checkout@v2
++
++ - name: Setup Dependencies
++ run: |
++ apt-get update
++ DEBIAN_FRONTEND=noninteractive sudo apt-get install -y \
++ cmake \
++ ninja-build
++
++ - name: Setup C++98 Environment
++ if: matrix.std == '98'
++ run: |
++ echo 'CXXFLAGS=-Wno-error=variadic-macros -Wno-error=long-long ${{env.CXXFLAGS}}' >> $GITHUB_ENV
++
++ - name: Configure
++ env:
++ CXXFLAGS: -Wall -Wextra -Wsign-conversion -Wtautological-compare -Wformat-nonliteral -Wundef -Werror -Wno-error=wasm-exception-spec ${{env.CXXFLAGS}}
++ run: |
++ cmake -S . -B build_${{matrix.build_type}} \
++ -DBUILD_SHARED_LIBS=${{matrix.lib == 'shared'}} \
++ -DCMAKE_AR=$(which emar) \
++ -DCMAKE_C_COMPILER=$(which emcc) \
++ -DCMAKE_CXX_COMPILER=$(which em++) \
++ -DCMAKE_CXX_STANDARD=${{matrix.std}} \
++ -DCMAKE_CXX_STANDARD_REQUIRED=ON \
++ -DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE=ONLY \
++ -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY \
++ -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=ONLY \
++ -DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER \
++ -DCMAKE_INSTALL_PREFIX=${{github.workspace}}/install \
++ -DCMAKE_RANLIB=$(which emranlib) \
++ -DWITH_CUSTOM_PREFIX=${{matrix.extra == 'custom-prefix'}} \
++ -G Ninja \
++ -Werror
++
++ - name: Build
++ run: |
++ cmake --build build_${{matrix.build_type}} \
++ --config ${{matrix.build_type}}
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 643a8b8a..ce6daa40 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -93,11 +93,11 @@ find_package (Unwind)
+ if (Unwind_FOUND)
+ set (HAVE_LIB_UNWIND 1)
+ else (Unwind_FOUND)
+- check_include_file_cxx (unwind.h HAVE_UNWIND_H)
+ # Check whether linking actually succeeds. ARM toolchains of LLVM unwind
+ # implementation do not necessarily provide the _Unwind_Backtrace function
+ # which causes the previous check to succeed but the linking to fail.
+ check_cxx_symbol_exists (_Unwind_Backtrace unwind.h HAVE__UNWIND_BACKTRACE)
++ check_cxx_symbol_exists (_Unwind_GetIP unwind.h HAVE__UNWIND_GETIP)
+ endif (Unwind_FOUND)
+
+ check_include_file_cxx (dlfcn.h HAVE_DLFCN_H)
+@@ -197,9 +197,10 @@ int main(void)
+ }
+ " HAVE___SYNC_VAL_COMPARE_AND_SWAP)
+
+-cmake_push_check_state (RESET)
+-set (CMAKE_REQUIRED_LIBRARIES Threads::Threads)
+-check_cxx_source_compiles ("
++if (Threads_FOUND)
++ cmake_push_check_state (RESET)
++ set (CMAKE_REQUIRED_LIBRARIES Threads::Threads)
++ check_cxx_source_compiles ("
+ #define _XOPEN_SOURCE 500
+ #include <pthread.h>
+ int main(void)
+@@ -209,8 +210,9 @@ int main(void)
+ pthread_rwlock_rdlock(&l);
+ return 0;
+ }
+-" HAVE_RWLOCK)
+-cmake_pop_check_state ()
++ " HAVE_RWLOCK)
++ cmake_pop_check_state ()
++endif (Threads_FOUND)
+
+ check_cxx_source_compiles ("
+ __declspec(selectany) int a;
+diff --git a/src/config.h.cmake.in b/src/config.h.cmake.in
+index b67e8a77..20b5f1c4 100644
+--- a/src/config.h.cmake.in
++++ b/src/config.h.cmake.in
+@@ -118,12 +118,12 @@
+ /* Define to 1 if you have the <unistd.h> header file. */
+ #cmakedefine HAVE_UNISTD_H ${HAVE_UNISTD_H}
+
+-/* Define if you have the <unwind.h> header file. */
+-#cmakedefine HAVE_UNWIND_H
+-
+ /* Define if you linking to _Unwind_Backtrace is possible. */
+ #cmakedefine HAVE__UNWIND_BACKTRACE
+
++/* Define if you linking to _Unwind_GetIP is possible. */
++#cmakedefine HAVE__UNWIND_GETIP
++
+ /* define if the compiler supports using expression for operator */
+ #cmakedefine HAVE_USING_OPERATOR
+
+diff --git a/src/glog/logging.h.in b/src/glog/logging.h.in
+index c6def152..098e28fe 100644
+--- a/src/glog/logging.h.in
++++ b/src/glog/logging.h.in
+@@ -97,7 +97,7 @@
+
+ @ac_google_start_namespace@
+
+-#if @ac_cv_have_uint16_t@ // the C99 format
++#if @ac_cv_have_stdint_h@ // the C99 format
+ typedef int32_t int32;
+ typedef uint32_t uint32;
+ typedef int64_t int64;
+@@ -1822,8 +1822,8 @@ GLOG_EXPORT void SetEmailLogging(LogSeverity min_severity,
+
+ // A simple function that sends email. dest is a commma-separated
+ // list of addressess. Thread-safe.
+-GLOG_EXPORT bool SendEmail(const char *dest,
+- const char *subject, const char *body);
++GLOG_EXPORT bool SendEmail(const char* dest, const char* subject,
++ const char* body);
+
+ GLOG_EXPORT const std::vector<std::string>& GetLoggingDirectories();
+
+diff --git a/src/glog/platform.h b/src/glog/platform.h
+index e6144119..7893c45d 100644
+--- a/src/glog/platform.h
++++ b/src/glog/platform.h
+@@ -50,6 +50,8 @@
+ #define GLOG_OS_NETBSD
+ #elif defined(__OpenBSD__)
+ #define GLOG_OS_OPENBSD
++#elif defined(__EMSCRIPTEN__)
++#define GLOG_OS_EMSCRIPTEN
+ #else
+ // TODO(hamaji): Add other platforms.
+ #error Platform not supported by glog. Please consider to contribute platform information by submitting a pull request on Github.
+diff --git a/src/logging.cc b/src/logging.cc
+index e65e80e9..1df1034a 100644
+--- a/src/logging.cc
++++ b/src/logging.cc
+@@ -2188,6 +2188,7 @@ void SetExitOnDFatal(bool value) {
+ } // namespace internal
+ } // namespace base
+
++#ifndef GLOG_OS_EMSCRIPTEN
+ // Shell-escaping as we need to shell out ot /bin/mail.
+ static const char kDontNeedShellEscapeChars[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+@@ -2222,14 +2223,14 @@ static string ShellEscape(const string& src) {
+ }
+ return result;
+ }
+-
++#endif
+
+ // use_logging controls whether the logging functions LOG/VLOG are used
+ // to log errors. It should be set to false when the caller holds the
+ // log_mutex.
+ static bool SendEmailInternal(const char*dest, const char *subject,
+ const char*body, bool use_logging) {
+-#ifndef __EMSCRIPTEN__
++#ifndef GLOG_OS_EMSCRIPTEN
+ if (dest && *dest) {
+ if ( use_logging ) {
+ VLOG(1) << "Trying to send TITLE:" << subject
+@@ -2275,6 +2276,12 @@ static bool SendEmailInternal(const char*dest, const char *subject,
+ }
+ }
+ }
++#else
++ (void)dest;
++ (void)subject;
++ (void)body;
++ (void)use_logging;
++ LOG(WARNING) << "Email support not available; not sending message";
+ #endif
+ return false;
+ }
+diff --git a/src/raw_logging.cc b/src/raw_logging.cc
+index 43159832..befeac89 100644
+--- a/src/raw_logging.cc
++++ b/src/raw_logging.cc
+@@ -59,11 +59,12 @@
+ # include <unistd.h>
+ #endif
+
+-#if (defined(HAVE_SYSCALL_H) || defined(HAVE_SYS_SYSCALL_H)) && (!(defined(GLOG_OS_MACOSX)))
+-# define safe_write(fd, s, len) syscall(SYS_write, fd, s, len)
++#if (defined(HAVE_SYSCALL_H) || defined(HAVE_SYS_SYSCALL_H)) && \
++ (!(defined(GLOG_OS_MACOSX))) && !defined(GLOG_OS_EMSCRIPTEN)
++#define safe_write(fd, s, len) syscall(SYS_write, fd, s, len)
+ #else
+- // Not so safe, but what can you do?
+-# define safe_write(fd, s, len) write(fd, s, len)
++// Not so safe, but what can you do?
++#define safe_write(fd, s, len) write(fd, s, len)
+ #endif
+
+ _START_GOOGLE_NAMESPACE_
+diff --git a/src/stacktrace_unwind-inl.h b/src/stacktrace_unwind-inl.h
+index fbb5f988..dc1665b4 100644
+--- a/src/stacktrace_unwind-inl.h
++++ b/src/stacktrace_unwind-inl.h
+@@ -73,7 +73,7 @@ static _Unwind_Reason_Code GetOneFrame(struct _Unwind_Context *uc, void *opq) {
+ if (targ->skip_count > 0) {
+ targ->skip_count--;
+ } else {
+- targ->result[targ->count++] = (void *) _Unwind_GetIP(uc);
++ targ->result[targ->count++] = reinterpret_cast<void *>(_Unwind_GetIP(uc));
+ }
+
+ if (targ->count == targ->max_depth) {
+diff --git a/src/symbolize.cc b/src/symbolize.cc
+index 51025018..f56e97c9 100644
+--- a/src/symbolize.cc
++++ b/src/symbolize.cc
+@@ -834,7 +834,7 @@ static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
+
+ _END_GOOGLE_NAMESPACE_
+
+-#elif defined(GLOG_OS_MACOSX) && defined(HAVE_DLADDR)
++#elif (defined(GLOG_OS_MACOSX) || defined(GLOG_OS_EMSCRIPTEN)) && defined(HAVE_DLADDR)
+
+ #include <dlfcn.h>
+ #include <cstring>
+diff --git a/src/utilities.h b/src/utilities.h
+index bd0ec632..760c142c 100644
+--- a/src/utilities.h
++++ b/src/utilities.h
+@@ -88,7 +88,7 @@
+
+ #if defined(HAVE_LIB_UNWIND)
+ # define STACKTRACE_H "stacktrace_libunwind-inl.h"
+-#elif defined(HAVE__UNWIND_BACKTRACE)
++#elif defined(HAVE__UNWIND_BACKTRACE) && defined(HAVE__UNWIND_GETIP)
+ # define STACKTRACE_H "stacktrace_unwind-inl.h"
+ #elif !defined(NO_FRAME_POINTER)
+ # if defined(__i386__) && __GNUC__ >= 2