xxHash/build/make

multiconf.make

multiconf.make is a self-contained Makefile include that lets you build the same targets under many different flag sets—debug vs release, ASan vs UBSan, GCC vs Clang, etc.—without the usual “object-file soup.” It hashes every combination of CC/CXX, CFLAGS/CXXFLAGS, CPPFLAGS, LDFLAGS and LDLIBS into a dedicated cache directory, so objects compiled with one configuration are never reused by another. Swap flags, rebuild, swap back—previous objects are still there and never collide.

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Key Benefits

Why it matters	What multiconf.make does
Isolated configs	Stores objects into cachedObjs/<hash>/, one directory per unique flag set.
Fast switching	Reusing an old config is instant—link only, no recompilation.
Header deps	Edits to headers trigger only needed rebuilds.
One-liner targets	Macros (c_program, cxx_program, …) hide all rule boilerplate.
Parallel-ready	Safe with make -j, no duplicate compiles of shared sources.

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Quick Start

1 · List your sources

C_SRCDIRS   := src src/cdeps    # all .c are in these directories
CXX_SRCDIRS := src src/cxxdeps  # all .cpp are in these directories

### 2 · Add and include

```make
# root/Makefile
include multiconf.make

3 · Declare targets

app:
$(eval $(call c_program,app,app.o obj1.o obj2.o))
test:
$(eval $(call cxx_program,test, test.o objcxx1.o objcxx2.o))

4 · Build any config you like

# Release with GCC
make CFLAGS="-O3"

# Debug with Clang + AddressSanitizer (new cache dir)
make CC=clang CFLAGS="-g -O0 -fsanitize=address"

# Switch back to GCC release (objects still valid, relink only)
make CFLAGS="-O3"

Objects for each command live in different sub-folders; nothing overlaps.

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Additional capabilities

Command	Description
make clean_cache	Wipe all cached objects & deps (full rebuild next time)
V=1	Show full compile/link commands

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