Compile errors on MacOS

[oneilm]

Compilation for C-Type complex number code in for GCC 6.2 running on MacOS:

g++-6 utils.cpp -c
g++-6 complexmulttiming.cpp utils.o -o complexmulttimingc -Ofast -funroll-loops -D USE_C_TYPE_COMPLEX
complexmulttiming.cpp: In function 'int main(int, char**)':
complexmulttiming.cpp:115:5: error: 'complex' was not declared in this scope
complex double *z = (complex double *)malloc(sizeof(complex double)*M);
^~~~~~~
complexmulttiming.cpp:115:5: note: suggested alternative:
In file included from /usr/local/Cellar/gcc/6.2.0/include/c++/6.2.0/ccomplex:39:0,
from /usr/local/Cellar/gcc/6.2.0/include/c++/6.2.0/complex.h:32,
from complexmulttiming.cpp:4:
/usr/local/Cellar/gcc/6.2.0/include/c++/6.2.0/complex:63:32: note: 'std::complex'
template class complex;
^~~~~~~
complexmulttiming.cpp:116:13: error: expected ';' before 'double'
complex double *z2 = (complex double )malloc(sizeof(complex double)M);
^~~~~~
complexmulttiming.cpp:118:7: error: 'z' was not declared in this scope
z[i] = data1_re[i] + Idata1_im[i];
^
complexmulttiming.cpp:119:7: error: 'z2' was not declared in this scope
z2[i] = data2_re[i] + Idata2_im[i];
^~
complexmulttiming.cpp:123:7: error: 'z' was not declared in this scope
z[i] = z[i-1] + z[i] * z2[i];
^
complexmulttiming.cpp:123:30: error: 'z2' was not declared in this scope
z[i] = z[i-1] + z[i] * z2[i];
^~
complexmulttiming.cpp:126:89: error: 'z' was not declared in this scope
printf("%lld C-type complex mults in %.3g s\n\tresult = %.12f + %.12fI\n",M,t,creal(z[M-1]),cimag(z[M-1]));
^
complexmulttiming.cpp:127:19: error: 'z2' was not declared in this scope
free(z); free(z2);
^~