[Ongoing] Rewrite frontend to use Flex/Bison

This is a merge of another experiment, so the changes are large:

- separated "modules" directory into frontend/backend
  - adjusted module names and moved files for this to happen
- removed modules lexer & parser
- removed all the unit tests (most were outdated)
- added Bison, flex, and C development tools to manifest.scm
- added lexer.l, a source file used by the flex utility with a functioning lexing implementation
- added parser.y, a source file used by the bison utility with a functioning parser implementation
- added node.c and node.h, which parser.y uses to construct an AST of a C source file (up to binary ops)
- added driver.c, a Guile-C interface that provides a module to scheme programs
- added a Makefile to make all of this
- added stuff to .gitignore

1 files changed, 8 insertions, 2 deletions

diff --git a/.gitignore b/.gitignore
index aff9071..c2b23bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,8 @@
-/writing-a-c-compiler-tests/
-/*.log
+writing-a-c-compiler-tests/
+build/
+src/frontend/lexer.c
+src/frontend/lexer.h
+src/frontend/parser.c
+src/frontend/parser.h
+src/frontend/parser.output
+libull.so
\ No newline at end of file