Propagate scheme-core changes with a single build

Due to a slip-up in build.sh (compiling flmain.c instead of flisp.c multiple
times), making changes in the Scheme core would require two build.sh runs
instead of one to end up in the final executable. flisp.c is the C file that
includes boot_image.h so it's the one that should get compiled multiple times.

scripts/build.sh

@@ -92,7 +92,7 @@ $CC $CFLAGS -c ../c/builtins.c
 $CC $CFLAGS -c ../c/dump.c
 $CC $CFLAGS -c ../c/env_unix.c
 $CC $CFLAGS -c ../c/equalhash.c
-$CC $CFLAGS -c ../c/flisp.c
+$CC $CFLAGS -c ../c/flmain.c
 $CC $CFLAGS -c ../c/hashing.c
 $CC $CFLAGS -c ../c/htable.c
 $CC $CFLAGS -c ../c/int2str.c
@@ -112,7 +112,7 @@ $CC $CFLAGS -c ../c/text_ini.c
 $CC $CFLAGS -c ../c/time_unix.c
 $CC $CFLAGS -c ../c/utf8.c
 
-$CC $CFLAGS -c ../c/flmain.c
+$CC $CFLAGS -c ../c/flisp.c
 $CC $LFLAGS -o upscheme $o_files
 
 { set +x; } 2>/dev/null
@@ -129,7 +129,7 @@ cd ../"$builddir"
 echo "Entering directory '$PWD'"
 set -x
 
-$CC $CFLAGS -c ../c/flmain.c
+$CC $CFLAGS -c ../c/flisp.c
 $CC $LFLAGS -o upscheme $o_files
 
 { set +x; } 2>/dev/null
@@ -146,7 +146,7 @@ cd ../"$builddir"
 echo "Entering directory '$PWD'"
 set -x
 
-$CC $CFLAGS -c ../c/flmain.c
+$CC $CFLAGS -c ../c/flisp.c
 $CC $LFLAGS -o upscheme $o_files
 
 { set +x; } 2>/dev/null