make it easier to compile projects that explicitly link with -lpthread

Makefile

@@ -18,7 +18,7 @@ MAKE    ?= make
 DESTDIR ?= /opt/ps5-payload-sdk
 
 TOPTARGETS := all clean install
-SUBDIRS    := crt sce_stubs libc libm include host
+SUBDIRS    := crt sce_stubs libc libm libpthread include host
 
 $(TOPTARGETS): $(SUBDIRS)
 

libpthread/Makefile

@@ -0,0 +1,43 @@
+#   Copyright (C) 2024 John Törnblom
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; see the file COPYING. If not see
+# <http://www.gnu.org/licenses/>.
+
+DESTDIR ?= /opt/ps5-payload-sdk
+
+ARS := llvm-ar-18 llvm-ar-17 llvm-ar-16 llvm-ar-15 llvm-ar
+ARS := $(foreach AR,$(ARS),$(if $(shell command -v $(AR) 2> /dev/null),$(AR)))
+AR  := $(firstword $(ARS))
+ifndef AR
+    $(error No suitable archiver found)
+endif
+
+# libpthread is provided by libkernel, which is always linked with.
+# Create an empty archive to make it easier to compile projects that
+# explicitly link with -lpthread
+
+ARCHIVE := libpthread.a
+
+all: $(ARCHIVE)
+
+$(ARCHIVE):
+	$(AR) rcs $@
+
+clean:
+	rm -f *.a *.o
+
+install: $(ARCHIVE)
+	install -d $(DESTDIR)/target/lib
+	install $^ $(DESTDIR)/target/lib
+