ARROW-4676: [C++] Add support for debug build with MinGW

[kou]

We need to suppress all warnings for debug build.

Messages:

cpp/src/arrow/util/cpu-info.cc: In function 'bool arrow::internal::RetrieveCacheSize(int64_t*)':
cpp/src/arrow/util/cpu-info.cc:127:12: error: conversion from 'long long unsigned int' to 'DWORD' {aka 'long unsigned int'} may change value [-Werror=conversion]
     offset += sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cpp/src/arrow/util/cpu-info.cc: In function 'bool arrow::internal::RetrieveCPUInfo(int64_t*, std::__cxx11::string*)':
cpp/src/arrow/util/cpu-info.cc:159:33: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   if (highest_extended_valid_id >= 0x80000004) {
       ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
cpp/src/arrow/util/cpu-info.cc:161:32: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
     for (int i = 0x80000002; i <= 0x80000004; ++i) {
                              ~~^~~~~~~~~~~~~
cpp/src/arrow/util/cpu-info.cc: At global scope:
cpp/src/arrow/util/cpu-info.cc:77:9: warning: 'int64_t arrow::internal::{anonymous}::ParseCPUFlags(const string&)' defined but not used [-Wunused-function]
 int64_t ParseCPUFlags(const std::string& values) {
         ^~~~~~~~~~~~~

cpp/src/arrow/util/io-util.cc: In function 'arrow::Status arrow::internal::FileRead(int, uint8_t*, int64_t, int64_t*)':
cpp/src/arrow/util/io-util.cc:408:57: error: conversion from 'size_t' {aka 'long long unsigned int'} to 'unsigned int' may change value [-Werror=conversion]
     int64_t ret = static_cast<int64_t>(read(fd, buffer, static_cast<size_t>(chunksize)));
                                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cpp/src/arrow/util/io-util.cc: In function 'arrow::Status arrow::internal::FileWrite(int, const uint8_t*, int64_t)':
cpp/src/arrow/util/io-util.cc:476:43: [ error: 75conversion from '%  size_tBuilding CXX object src/arrow/CMakeFiles/arrow_objlib.dir/util/memory.cc.obj' {aka '
long long unsigned int'} to 'unsigned int' may change value [-Werror=conversion]
         write(fd, buffer + bytes_written, static_cast<size_t>(chunksize)));
                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[codecov-io]

Codecov Report

Merging #3750 into master will decrease coverage by 0.18%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #3750      +/-   ##
=========================================
- Coverage   87.78%   87.6%   -0.19%     
=========================================
  Files         607     707     +100     
  Lines       66049   86486   +20437     
  Branches     1227    1227              
=========================================
+ Hits        57982   75764   +17782     
- Misses       7954   10609    +2655     
  Partials      113     113

Impacted Files	Coverage Δ
cpp/src/arrow/util/cpu-info.cc	75% <ø> (ø)	⬆️
cpp/src/arrow/util/io-util.cc	81.56% <ø> (ø)	⬆️
cpp/src/arrow/compute/kernels/sum.cc	72.99% <0%> (-19.6%)	⬇️
cpp/src/arrow/util/bit-util.h	95.62% <0%> (-4.38%)	⬇️
cpp/src/arrow/util/key_value_metadata.cc	98.59% <0%> (-1.41%)	⬇️
cpp/src/arrow/util/bpacking.h	99.84% <0%> (-0.01%)	⬇️
python/pyarrow/ipc.pxi	66.15% <0%> (ø)
python/pyarrow/tests/test_deprecations.py	100% <0%> (ø)
python/pyarrow/tests/test_plasma.py	96.51% <0%> (ø)
python/pyarrow/tests/pandas_examples.py	95.83% <0%> (ø)
... and 157 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6fb4cd0...4dc7fc7. Read the comment docs.

[kou]

No objection.
I'll merge this.