tests: check for exported symbols in the data section as well

The PowerPC64 ELFv1 ABI puts the function descriptor symbols there,
but why restrict the consistency check to the text section anyway?

Signed-off-by: Ferenc Wágner <wferi@debian.org>

libknet/tests/api-test-coverage

@@ -12,7 +12,10 @@ builddir="$2"/libknet/tests
 
 headerapicalls="$(grep knet_ "$srcdir"/../libknet.h | grep -v "^ \*" | grep -v ^struct | grep -v "^[[:space:]]" | grep -v typedef | sed -e 's/(.*//g' -e 's/^const //g' -e 's/\*//g' | awk '{print $2}')"
 
-exportedapicalls="$(nm -B -D "$builddir"/../.libs/libknet.so | grep ' T ' | awk '{print $3}')"
+# The PowerPC64 ELFv1 ABI defines the address of a function as that of a
+# function descriptor defined in .opd, a data (D) section.  Other ABIs
+# use the entry address of the function itself in the text (T) section.
+exportedapicalls="$(nm -B -D "$builddir"/../.libs/libknet.so | grep ' [DT] ' | awk '{print $3}')"
 
 echo "Checking for exported symbols NOT available in header file"