make fails on Cygwin

`make` fails on Cygwin:

~~~
$ make
make --no-print-directory all-am
/usr/lib/gcc/x86_64-pc-cygwin/12/../../../../x86_64-pc-cygwin/bin/ld: ./.libs/libisal.a(igzip.o): in function `isal_adler32_bam1':
/home/ota/tmp/r/isa-l/igzip/igzip.c:127:(.text+0x230): undefined reference to `isal_adler32'
:
/home/ota/tmp/r/isa-l/igzip/igzip_inflate.c:2369:(.text+0x4267): undefined reference to `decode_huffman_code_block_stateless'
/usr/lib/gcc/x86_64-pc-cygwin/12/../../../../x86_64-pc-cygwin/bin/ld: /home/ota/tmp/r/isa-l/igzip/igzip_inflate.c:2301:(.text+0x42f7): undefined reference to `decode_huffman_code_block_stateless'
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:3529: programs/igzip.exe] Error 1
make: *** [Makefile:2410: all] Error 2
~~~

With this patch it builds:

~~~
diff --git a/igzip/Makefile.am b/igzip/Makefile.am
index 900034d..4de0fa3 100644
--- a/igzip/Makefile.am
+++ b/igzip/Makefile.am
@@ -135,7 +135,7 @@ lsrc += igzip/huff_codes.c

# Include tools and tests using the reference inflate
other_tests += igzip/igzip_inflate_test
-lsrc += igzip/igzip_inflate.c
+lsrc += igzip/igzip_inflate.c igzip/igzip_base_aliases.c igzip/proc_heap_base.c crc/crc_base_aliases.c
other_src += igzip/checksum_test_ref.h

igzip_perf: LDLIBS += -lz
~~~

But I am not sure if this is the best place to put those filenames.

Patch is hereby licensed as CC0 (public domain).