The compiler is written in Finch, and nothing else: src/*.fch, built from a seed

boot/ is src/ now. The C++ compiler and CMake are gone from this branch (they are on before-bootstrap).
bootstrap/build.sh builds the compiler from bootstrap/<system>.ll -- the compiler's own LLVM IR -- then builds
it with itself and checks the two come out identical. bootstrap/build.sh seed writes the seed anew.

The driver is complete: the runtime is compiled once and kept in ~/.cache/finch; a program's own C files,
.o and .a files and frameworks link along; a linker failure is read and answered with  link "lib"  or the
library that is missing. The old tests/fail diagnostics are all in again (a missing import, a str compared with
null, 'write just the library's name', a map key that is a float, non-ASCII names, ...).

tests/run.sh is the one test runner: programs, refusals, -g builds and the shared library. 106 passed.

tests/shared.sh

@@ -4,6 +4,7 @@
 set -e
 cd "$(dirname "$0")/shared"
 FINCH=${FINCH:-../../build/finch}
+export FINCH_RT=${FINCH_RT:-$PWD/../../runtime/finch_rt.c}
 tmp=$(mktemp -d)
 trap 'rm -rf "$tmp"' EXIT
 "$FINCH" build mod.fch --shared -o "$tmp/libmod.so"