Fix clang build error in bitops.c

[rjd15372]

In a recent PR #1741 the new header <immintrin.h> was added, which transitively includes <mm_malloc.h> header, where a function called _mm_malloc(...) makes a call to the malloc function.

The Valkey server code explicitly sets the malloc function as a deprecated function in server.h:

void *malloc(size_t size) __attribute__((deprecated));

The Valkey server code is then compiled with
-Werror=deprecated-declarations option to detect the uses of deprecated functions like malloc, and due to this, when the bitops.c file is compiled with Clang, fails with the following error:

In file included from bitops.c:33:
In file included from /usr/lib/llvm-18/lib/clang/18/include/immintrin.h:26:
In file included from /usr/lib/llvm-18/lib/clang/18/include/xmmintrin.h:31:
/usr/lib/llvm-18/lib/clang/18/include/mm_malloc.h:35:12: error: 'malloc' is deprecated [-Werror,-Wdeprecated-declarations]
   35 |     return malloc(__size);
      |            ^
./server.h:3874:42: note: 'malloc' has been explicitly marked deprecated here
 3874 | void *malloc(size_t size) __attribute__((deprecated));

There is a difference in behavior though, between GCC and Clang. The bitops.c file compiles successfully with GCC.

I don't know exactly why GCC does not issue a warning in this case. My best guess is that GCC does not issue warnings from code of the standard library.

To fix the build error in clang, we explicitly use pragma macro to tell clang to ignore deprecated declarations warnings in bitops.c.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.13%. Comparing base (4966357) to head (bae74c6).
Report is 3 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1794      +/-   ##
============================================
+ Coverage     70.97%   71.13%   +0.16%     
============================================
  Files           123      123              
  Lines         65645    65648       +3     
============================================
+ Hits          46590    46698     +108     
+ Misses        19055    18950     -105     

Files with missing lines	Coverage Δ
src/bitops.c	94.05% <ø> (+4.05%)	⬆️

... and 14 files with indirect coverage changes