Add CXX_32 and CXX_64 variables in the makefiles

Instead of explicitly passing -m32 and -m64 to the CXX invocation,
define CXX_32 and CXX_64 as "CXX -m32" and "CXX -m64", respectively.

This allows easily using a cross GCC toolchain instead of GCC's multilib
support, for example by defining CXX_32=i686-linux-gnu-gcc, and
CXX_64=x86_64-linux-gnu-gcc.

See
<https://lists.debian.org/msgid-search/20250316194848.GA2297362@subdivi.de>
and related messages for some more context on why multilib (-m32 and
-m64) might get removed from Debian in the future, in favour of cross
compilers.

sample/Makefile

diff --git a/sample/Makefile b/sample/Makefile
index ff94b3a..c595b60 100644
--- a/sample/Makefile
+++ b/sample/Makefile
@@ -1,5 +1,7 @@
 XBYAK_INC=../xbyak/xbyak.h
 CXX?=g++
+CXX_32=$(CXX) -m32
+CXX_64=$(CXX) -m64
 
 BOOST_EXIST=$(shell echo "#include <boost/spirit/core.hpp>" | $(CXX) -x c++ -c - 2>/dev/null && echo 1)
 UNAME_M=$(shell uname -m)
@@ -56,49 +58,49 @@
 CFLAGS=-g -O2 -fomit-frame-pointer -Wall -I../ $(CFLAGS_WARN) $(CXXFLAGS) $(CPPFLAGS) $(LDFLAGS)
 
 test:
-	$(CXX) $(CFLAGS) test0.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) test0.cpp -o $@
 
 quantize:
-	$(CXX) $(CFLAGS) quantize.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) quantize.cpp -o $@
 
 calc:
-	$(CXX) $(CFLAGS) calc.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) calc.cpp -o $@
 calc64:
-	$(CXX) $(CFLAGS) calc.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) calc.cpp -o $@
 calc2:
-	$(CXX) $(CFLAGS) calc2.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) calc2.cpp -o $@
 calc2_64:
-	$(CXX) $(CFLAGS) calc2.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) calc2.cpp -o $@
 
 bf:
-	$(CXX) $(CFLAGS) bf.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) bf.cpp -o $@
 bf64:
-	$(CXX) $(CFLAGS) bf.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) bf.cpp -o $@
 
 memfunc:
-	$(CXX) $(CFLAGS) memfunc.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) memfunc.cpp -o $@
 memfunc64:
-	$(CXX) $(CFLAGS) memfunc.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) memfunc.cpp -o $@
 
 toyvm:
-	$(CXX) $(CFLAGS) toyvm.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) toyvm.cpp -o $@
 
 test64:
-	$(CXX) $(CFLAGS) test0.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) test0.cpp -o $@
 test_util:
-	$(CXX) $(CFLAGS) test_util.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) test_util.cpp -o $@
 test_util64:
-	$(CXX) $(CFLAGS) test_util.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) test_util.cpp -o $@
 static_buf:
-	$(CXX) $(CFLAGS) static_buf.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) static_buf.cpp -o $@
 static_buf64:
-	$(CXX) $(CFLAGS) static_buf.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) static_buf.cpp -o $@
 jmp_table:
-	$(CXX) $(CFLAGS) jmp_table.cpp -o $@ -m32
+	$(CXX_32) $(CFLAGS) jmp_table.cpp -o $@
 jmp_table64:
-	$(CXX) $(CFLAGS) jmp_table.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) jmp_table.cpp -o $@
 memfd:
-	$(CXX) $(CFLAGS) memfd.cpp -o $@ -m64
+	$(CXX_64) $(CFLAGS) memfd.cpp -o $@
 profiler: profiler.cpp ../xbyak/xbyak_util.h
 	$(CXX) $(CFLAGS) profiler.cpp -o $@
 profiler-vtune: profiler.cpp ../xbyak/xbyak_util.h

test/Makefile

diff --git a/test/Makefile b/test/Makefile
index c8a15b8..769eb8a 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,5 +1,7 @@
 # To compile with -m32
 # apt install g++-multilib
+CXX_32 = $(CXX) -m32
+CXX_64 = $(CXX) -m64
 TARGET = make_nm normalize_prefix bad_address misc cvt_test cvt_test32 noexception misc32 detect_x32 avx10_test
 XBYAK_INC=../xbyak/xbyak.h ../xbyak/xbyak_mnemonic.h ../xbyak/xbyak_util.h
 UNAME_S=$(shell uname -s)
@@ -39,13 +41,13 @@
 test_mmx: test_mmx.cpp $(XBYAK_INC)
 	$(CXX) $(CFLAGS) test_mmx.cpp -o $@ -lpthread
 jmp: jmp.cpp $(XBYAK_INC)
-	$(CXX) $(CFLAGS) $< -o $@ -m32
+	$(CXX_32) $(CFLAGS) $< -o $@
 jmp64: jmp.cpp $(XBYAK_INC)
-	$(CXX) $(CFLAGS) $< -o $@ -m64
+	$(CXX_64) $(CFLAGS) $< -o $@
 address: address.cpp $(XBYAK_INC)
-	$(CXX) $(CFLAGS) $< -o $@ -m32
+	$(CXX_32) $(CFLAGS) $< -o $@
 address64: address.cpp $(XBYAK_INC)
-	$(CXX) $(CFLAGS) $< -o $@ -m64
+	$(CXX_64) $(CFLAGS) $< -o $@
 bad_address: bad_address.cpp $(XBYAK_INC)
 	$(CXX) $(CFLAGS) $< -o $@
 misc: misc.cpp $(XBYAK_INC)