我正在尝试安装clang和llvm，因为它们是PySide2的依赖项。使用macports，我安装了llvm，并且安装了clang和port表明它们处于活动状态。
The following ports are currently installed:
bzip2 @1.0.6_0 (active)
cctools @895_4+llvm39 (active)
clang-4.0 @4.0.0_0+analyzer+libstdcxx (active)
clang_select @2_0 (active)
db48 @4.8.30_4 (active)
expat @2.2.1_1 (active)
gcc6 @6.3.0_2 (active)
gcc_select @0.1_8 (active)
gdbm @1.13_3 (active)
gettext @0.19.8.1_0 (active)
gmp @6.1.2_0 (active)
isl @0.18_0 (active)
ld64 @3_0 (active)
ld64-latest @274.2_1+llvm39 (active)
libcxx @3.9.1_0+universal (active)
libedit @20170329-3.1_0 (active)
libffi @3.2.1_0 (active)
libgcc @6.3.0_0 (active)
libiconv @1.15_0 (active)
libmpc @1.0.3_0 (active)
libomp @3.9.1_0+universal (active)
libxml2 @2.9.4_1 (active)
llvm-3.9 @3.9.1_3 (active)
llvm-4.0 @4.0.0_0 (active)
llvm_select @2_0 (active)
mpfr @3.1.5_0 (active)
ncurses @6.0-20170610_0 (active)
openssl @1.0.2l_0 (active)
perl5 @5.24.1_0+perl5_24 (active)
perl5.24 @5.24.1_0 (active)
python2_select @0.0_2 (active)
python27 @2.7.13_1 (active)
python_select @0.3_7 (active)
readline @7.0.003_1 (active)
sqlite3 @3.19.3_0 (active)
xar @1.5.2_2 (active)
xz @5.2.3_0 (active)
zlib @1.2.11_0 (active)
但是，我无法从命令行运行llvm-config，所以llvm实际安装了吗？或链接有问题吗？