Re: [PATCH] Git.pm: Support for perl/ being built by a different compiler

Sun CC 5.8 fails with a strange error compiling diff-delta.c that
looks like an error in Sun's compiler to me:

$ cc -V
cc: Sun C 5.8 Patch 121015-02 2006/03/29

$ cc -o diff-delta.o -c -I/opt/gnu/include -D__EXTENSIONS__ \
-DSHA1_HEADER='<openssl/sha.h>' -DNO_STRCASESTR -DNO_STRLCPY \
-DNO_SETENV -DNO_UNSETENV diff-delta.c
"diff-delta.c", line 251: identifier redeclared: create_delta
        current : function(pointer to const struct delta_index \
{pointer to const void src_buf, unsigned long src_size, \
unsigned int hash_mask, array[-1] of pointer to struct index_entry {..} hash},\
pointer to const void, unsigned long, pointer to unsigned long, \
unsigned long) returning pointer to void
        previous: function(pointer to const struct delta_index \
{pointer to const void src_buf, unsigned long src_size, \
unsigned int hash_mask, array[-1] of pointer to struct index_entry {..} hash},\
pointer to const void, unsigned long, pointer to unsigned long, \
unsigned long) returning pointer to void : "delta.h", line 37
cc: acomp failed for diff-delta.c
make: *** [diff-delta.o] Error 2

Yes, the two prototypes are identical.  Seems like the compiler has
problems with the opaque struct.  When I played around with it, I
was surprised when I found that Sun CC actually compiled this file
after I removed the const qualifier from the first parameter of the
create_delta() function.  Does anybody have a better explanation
than an error in the compiler?

Regards,
Dennis

diff --git a/delta.h b/delta.h
index 7b3f86d..ec9147c 100644
--- a/delta.h
+++ b/delta.h

@@ -34,11 +34,12 @@ extern void free_delta_index(struct delt
  * must be freed by the caller.
  */
 extern void *
-create_delta(const struct delta_index *index,
+create_delta(struct delta_index *index,
             const void *buf, unsigned long bufsize,
             unsigned long *delta_size, unsigned long max_delta_size);

-/*
+/*l
+
  * diff_delta: create a delta from source buffer to target buffer
  *
  * If max_delta_size is non-zero and the resulting delta is to be larger

diff --git a/diff-delta.c b/diff-delta.c
index 8b9172a..802be76 100644
--- a/diff-delta.c
+++ b/diff-delta.c

@@ -245,7 +245,7 @@ void free_delta_index(struct delta_index
 #define MAX_OP_SIZE    (5 + 5 + 1 + RABIN_WINDOW + 7)

 void *
-create_delta(const struct delta_index *index,
+create_delta(struct delta_index *index,
             const void *trg_buf, unsigned long trg_size,
             unsigned long *delta_size, unsigned long max_size)
 {