gstlal_autocorrelation_chi2.c: modify use of GSL_REAL/GSL_IMAG for GSL 2.7 compatibility
As mentioned in #78 (closed), compiling with gstlal with GSL 2.7 causes build issues of the form:
In file included from gstlal_autocorrelation_chi2.c:66:
gstlal_autocorrelation_chi2.c: In function 'gstlal_bankcorrelation_chi2_compute_norms':
gstlal_autocorrelation_chi2.c:493:19: error: lvalue required as unary '&' operand
493 | cij = ((float) GSL_REAL(gsl_matrix_complex_get(bankcorrelation_matrix, i, channel)) + (float) GSL_IMAG(gsl_matrix_complex_get(bankcorrelation_matrix, i, channel)) * I);
| ^~~~~~~~
gstlal_autocorrelation_chi2.c:493:98: error: lvalue required as unary '&' operand
493 | cij = ((float) GSL_REAL(gsl_matrix_complex_get(bankcorrelation_matrix, i, channel)) + (float) GSL_IMAG(gsl_matrix_complex_get(bankcorrelation_matrix, i, channel)) * I);
| ^~~~~~~~
gstlal_autocorrelation_chi2.c: In function 'gstlal_bankcorrelation_chi2_from_peak_float':
gstlal_autocorrelation_chi2.c:530:19: error: lvalue required as unary '&' operand
530 | cij = ((float) GSL_REAL(gsl_matrix_complex_get(bcmat, i, j)) + (float) GSL_IMAG(gsl_matrix_complex_get(bcmat, i, j)) * I);
| ^~~~~~~~
gstlal_autocorrelation_chi2.c:530:75: error: lvalue required as unary '&' operand
530 | cij = ((float) GSL_REAL(gsl_matrix_complex_get(bcmat, i, j)) + (float) GSL_IMAG(gsl_matrix_complex_get(bcmat, i, j)) * I);
| ^~~~~~~~
make[2]: *** [Makefile:696: libgstlal_la-gstlal_autocorrelation_chi2.lo] Error 1
This solution takes a similar approach as lalsuite in lalsuite#451 (closed) and lalsuite!1634 (merged).
Closes #78 (closed).