compile pcre2 vendor dep without autotools

doubt autotools is generating much beyond the generic forms of
pcre2.h and config.h on most modern systems. compiling it ourselves
is neater and requires less build deps.

Makefile

@@ -3,7 +3,7 @@ prefix?=/usr/local
 mle_cflags:=-std=c99 -Wall -Wextra -pedantic -Wno-pointer-arith -Wno-unused-result -Wno-unused-parameter -g -O0 -D_GNU_SOURCE -DPCRE2_CODE_UNIT_WIDTH=8 -I. $(CFLAGS) $(CPPFLAGS)
 mle_ldflags:=$(LDFLAGS)
 mle_dynamic_libs:=-lpcre2-8 -llua5.4
-mle_static_libs:=vendor/pcre2/.libs/libpcre2-8.a vendor/lua/liblua5.4.a
+mle_static_libs:=vendor/pcre2/libpcre2-8.a vendor/lua/liblua5.4.a
 mle_ldlibs:=-lm $(LDLIBS)
 mle_objects:=$(patsubst %.c,%.o,$(wildcard *.c))
 mle_objects_no_main:=$(filter-out main.o,$(mle_objects))

README.md

@@ -50,7 +50,7 @@ Runs on Linux, Windows (Cygwin or WSL), FreeBSD, macOS, and more.
 
 ### Building
 
-    $ sudo apt install git build-essential libtool automake # or equivalent
+    $ sudo apt install git build-essential # install git, make, gcc, libc-dev
     $
     $ git clone --recursive https://github.com/adsr/mle.git
     $ cd mle

vendor/Makefile

@@ -1,24 +1,47 @@
 lua_cflags:=-std=c99 -Wall -Wextra -g -O3 -DLUA_USE_POSIX $(CFLAGS)
 lua_objects:=$(patsubst lua/%.c,lua/%.o,$(filter-out lua/lua.c lua/onelua.c, $(wildcard lua/*.c)))
 
-all: uthash/src/utlist.h pcre2/.libs/libpcre2-8.a lua/liblua5.4.a
+pcre2_cflags:=-std=c99 -Wall -Wextra -g -O3 -DPCRE2_CODE_UNIT_WIDTH=8 -DSUPPORT_JIT -DHAVE_CONFIG_H $(CFLAGS)
+pcre2_objects:=$(addprefix pcre2/src/, \
+	pcre2_auto_possess.o pcre2_chartables.o pcre2_compile.o pcre2_config.o \
+	pcre2_context.o pcre2_convert.o pcre2_dfa_match.o pcre2_error.o pcre2_extuni.o \
+	pcre2_find_bracket.o pcre2_jit_compile.o pcre2_maketables.o pcre2_match.o \
+	pcre2_match_data.o pcre2_newline.o pcre2_ord2utf.o pcre2_pattern_info.o \
+	pcre2_script_run.o pcre2_serialize.o pcre2_string_utils.o pcre2_study.o \
+	pcre2_substitute.o pcre2_substring.o pcre2_tables.o pcre2_ucd.o pcre2_ucptables.o \
+	pcre2_valid_utf.o pcre2_xclass.o)
+
+all: uthash/src/utlist.h pcre2/libpcre2-8.a lua/liblua5.4.a
 
 uthash/src/utlist.h:
 	command -v git && git submodule update --init
 
-pcre2/.libs/libpcre2-8.a:
-	cd pcre2 && ./autogen.sh && ./configure && $(MAKE)
-
 lua/liblua5.4.a: $(lua_objects)
 	$(AR) rcs $@ $(lua_objects)
 
 $(lua_objects): %.o: %.c
 	$(CC) -c $(lua_cflags) $< -o $@
 
+pcre2/libpcre2-8.a: $(pcre2_objects)
+	$(AR) rcs $@ $(pcre2_objects)
+
+pcre2/src/pcre2.h: pcre2/src/pcre2.h.generic
+	cp -f $< $@
+
+pcre2/src/config.h: pcre2/src/config.h.generic
+	cp -f $< $@
+
+pcre2/src/pcre2_chartables.c: pcre2/src/pcre2_chartables.c.dist
+	cp -f $< $@
+
+$(pcre2_objects): %.o: %.c
+	$(CC) -c $(pcre2_cflags) $< -o $@
+
+$(pcre2_objects:.o=.c): pcre2/src/pcre2.h pcre2/src/config.h
+
 clean:
+	rm -f pcre2/libpcre2-8.a pcre2/src/pcre2.h pcre2/src/config.h pcre2/src/pcre2_chartables.c $(pcre2_objects)
 	rm -f lua/liblua5.4.a $(lua_objects)
-	rm -f pcre2/src/config.h.in~
-	-test -f pcre2/Makefile && $(MAKE) -C pcre2 clean
 
 .NOTPARALLEL: