package/fluent-bit: add support for non glibc toolchain

- require threads and dynamic library support
- require sync_4 support
- provide fts.h through musl-fts

static_assert is not available if no C++ toolchain or no glibc
is used, so add two patches to fix this

Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/fluent-bit/0001-lib-cfl-fixup-static_assert.patch

@@ -0,0 +1,33 @@
+From e4f825dd9e952f4a056bf89342049e67102ae6bb Mon Sep 17 00:00:00 2001
+From: Thomas Devoogdt <thomas.devoogdt@barco.com>
+Date: Wed, 1 Feb 2023 11:38:15 +0100
+Subject: [PATCH] lib: cfl: fixup static_assert
+
+"undefined reference to 'static_assert'"
+
+Not defined when using uClibc or if not C++ >= 11.
+
+upstream: https://github.com/Cyan4973/xxHash/commit/6189ecd3d44a693460f86280ccf49d33cb4b18e1
+
+Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
+---
+ lib/cfl/lib/xxhash/xxhash.h | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/lib/cfl/lib/xxhash/xxhash.h b/lib/cfl/lib/xxhash/xxhash.h
+index 08ab79457..511c4d12b 100644
+--- a/lib/cfl/lib/xxhash/xxhash.h
++++ b/lib/cfl/lib/xxhash/xxhash.h
+@@ -1546,8 +1546,7 @@ static void* XXH_memcpy(void* dest, const void* src, size_t size)
+ /* note: use after variable declarations */
+ #ifndef XXH_STATIC_ASSERT
+ #  if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)    /* C11 */
+-#    include <assert.h>
+-#    define XXH_STATIC_ASSERT_WITH_MESSAGE(c,m) do { static_assert((c),m); } while(0)
++#    define XXH_STATIC_ASSERT_WITH_MESSAGE(c,m) do { _Static_assert((c),m); } while(0)
+ #  elif defined(__cplusplus) && (__cplusplus >= 201103L)            /* C++11 */
+ #    define XXH_STATIC_ASSERT_WITH_MESSAGE(c,m) do { static_assert((c),m); } while(0)
+ #  else
+-- 
+2.34.1
+

package/fluent-bit/0002-lib-c-ares-fixup-static_assert.patch

@@ -0,0 +1,56 @@
+From f55f9bf6d9201169d2e5d3782068b03ff17dec90 Mon Sep 17 00:00:00 2001
+From: Thomas Devoogdt <thomas.devoogdt@barco.com>
+Date: Wed, 1 Feb 2023 11:26:56 +0100
+Subject: [PATCH] lib: c-ares: fixup static_assert
+
+"undefined reference to 'static_assert'"
+
+Not defined when using uClibc or if not C++ >= 11.
+
+upstream: https://github.com/c-ares/c-ares/issues/504
+
+Signed-off-by: Thomas Devoogdt <thomas.devoogdt@barco.com>
+---
+ lib/c-ares-1.19.0/configure                      | 4 ++++
+ lib/c-ares-1.19.0/m4/ax_cxx_compile_stdcxx_11.m4 | 3 +++
+ 2 files changed, 7 insertions(+)
+
+diff --git a/lib/c-ares-1.19.0/configure b/lib/c-ares-1.19.0/configure
+index 4c5e1a966..58712ec34 100755
+--- a/lib/c-ares-1.19.0/configure
++++ b/lib/c-ares-1.19.0/configure
+@@ -6317,6 +6317,8 @@ else $as_nop
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ /* end confdefs.h.  */
+ 
++#define static_assert _Static_assert
++
+   template <typename T>
+     struct check
+     {
+@@ -6394,6 +6396,8 @@ else $as_nop
+          cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ /* end confdefs.h.  */
+ 
++#define static_assert _Static_assert
++
+   template <typename T>
+     struct check
+     {
+diff --git a/lib/c-ares-1.19.0/m4/ax_cxx_compile_stdcxx_11.m4 b/lib/c-ares-1.19.0/m4/ax_cxx_compile_stdcxx_11.m4
+index 229de3091..fe4a11c67 100644
+--- a/lib/c-ares-1.19.0/m4/ax_cxx_compile_stdcxx_11.m4
++++ b/lib/c-ares-1.19.0/m4/ax_cxx_compile_stdcxx_11.m4
+@@ -37,6 +37,9 @@
+ #serial 9
+ 
+ m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[
++
++#define static_assert _Static_assert
++
+   template <typename T>
+     struct check
+     {
+-- 
+2.34.1
+

package/fluent-bit/Config.in

@@ -1,6 +1,9 @@
 config BR2_PACKAGE_FLUENT_BIT
 	bool "fluent-bit"
-	depends on BR2_TOOLCHAIN_USES_GLIBC
+	depends on BR2_TOOLCHAIN_HAS_THREADS
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
+	depends on !BR2_STATIC_LIBS # dlfcn.h
+	select BR2_PACKAGE_MUSL_FTS if !BR2_TOOLCHAIN_USES_GLIBC
 	select BR2_PACKAGE_OPENSSL
 	select BR2_PACKAGE_LIBYAML
 	help
@@ -29,5 +32,6 @@ config BR2_PACKAGE_FLUENT_BIT_WASM
 
 endif
 
-comment "fluent-bit needs a glibc toolchain"
-	depends on !BR2_TOOLCHAIN_USES_GLIBC
+comment "fluent-bit needs a toolchain w/ threads, dynamic library"
+	depends on BR2_TOOLCHAIN_HAS_SYNC_4
+	depends on !BR2_TOOLCHAIN_HAS_THREADS || BR2_STATIC_LIBS

package/fluent-bit/fluent-bit.mk

@@ -49,12 +49,19 @@ FLUENT_BIT_CONF_OPTS += \
 	-DCMAKE_C_FLAGS="$(TARGET_CFLAGS) -U_FILE_OFFSET_BITS" \
 	-DCMAKE_CXX_FLAGS="$(TARGET_CXXFLAGS) -U_FILE_OFFSET_BITS"
 
+ifeq ($(BR2_TOOLCHAIN_USES_GLIBC),)
+FLUENT_BIT_DEPENDENCIES += musl-fts
+FLUENT_BIT_LDFLAGS += -lfts
+endif
+
 # Uses __atomic_compare_exchange_8
 ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
-FLUENT_BIT_CONF_OPTS += \
-	-DCMAKE_EXE_LINKER_FLAGS=-latomic
+FLUENT_BIT_LDFLAGS += -latomic
 endif
 
+FLUENT_BIT_CONF_OPTS += \
+	-DCMAKE_EXE_LINKER_FLAGS="$(FLUENT_BIT_LDFLAGS)"
+
 define FLUENT_BIT_INSTALL_INIT_SYSV
 	$(INSTALL) -D -m 0755 package/fluent-bit/S99fluent-bit \
 		$(TARGET_DIR)/etc/init.d/S99fluent-bit