clang warning: macro expansion producing 'defined' has undefined behavior

[nereocystis]

Your Environment

• Operating System and version: Ubuntu 17.10

• Compiler: clang version 4.0.1-6 (tags/RELEASE_401/final)
  Target: x86_64-pc-linux-gnu
  Thread model: posix
  InstalledDir: /usr/bin

• PCL Version: HEAD

I used the following cmake command:

Expected Behavior

No warning for below line, when compiling

Current Behavior

clang warnings point out a problem with io/src/lzf.cpp, used "defined"
as part of a macro expension has undefined results.

                   ^

/home/kevin/src/pcl/io/src/lzf.cpp:58:6: error: macro expansion producing
'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/home/kevin/src/pcl/io/src/lzf.cpp:57:43: note: expanded from macro
'STRICT_ALIGN'
#define STRICT_ALIGN !(defined(__i386) || defined (__amd64))
^
/home/kevin/src/pcl/io/src/lzf.cpp:137:5: error: macro expansion producing
'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
#if STRICT_ALIGN
^
/home/kevin/src/pcl/io/src/lzf.cpp:57:24: note: expanded from macro
'STRICT_ALIGN'
#define STRICT_ALIGN !(defined(__i386) || defined (__amd64))
^
/home/kevin/src/pcl/io/src/lzf.cpp:137:5: error: macro expansion producing
'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/home/kevin/src/pcl/io/src/lzf.cpp:57:43: note: expanded from macro
'STRICT_ALIGN'
#define STRICT_ALIGN !(defined(__i386) || defined (__amd64))
^
4 errors generated.

Possible Solution

Fix is easy.
#define should be rewritten. I will soon submit a pull request.

Code to Reproduce

cmake .. -DCMAKE_CXX_COMPILER:FILEPATH=/usr/bin/clang++ -DCMAKE_C_COMPILER:FILEPATH=/usr/bin/clang -DCMAKE_CXX_FLAGS:STRING="-fno-omit-frame-pointer -Wno-overloaded-virtual -Wno-bind-to-temporary-copy -Wno-unused -Wno-conversion -Werror -Wno-error=dynamic-class-memaccess" -DCMAKE_C_FLAGS:STRING="-fno-omit-frame-pointer -Wno-overloaded-virtual -Wno-bind-to-temporary-copy -Wno-unused -Wno-conversion -Werror -Wno-error=dynamic-class-memaccess" -DBUILD_global_tests=ON

make

Context

Different compilers will produce inconsistent results with lzf.cpp