Add missing PCP include path for dynamic PMDA

The dynamic PMDA uses internal PCP headers (libpcp.h) that require
-I$(PCP_INC_DIR) to be found. The GNUmakefile.install was stripping
all -I flags from builddefs and only adding back -I$(PCP_INC_DIR)/..
which works for public headers like <pcp/pmapi.h> but not for internal
headers like "libpcp.h".

This was causing compilation failures when building the dynamic PMDA
from the installed testsuite with: fatal error: 'libpcp.h' file not found

Author: tallpsmith

qa/pmdas/dynamic/GNUmakefile.install

@@ -22,7 +22,8 @@ ifneq "$(PCP_INC_DIR)" "/usr/include/pcp"
 # for cc add -I<run-time-include-dir> (need /.. at the end so
 # #include <pcp/foo.h> works) when $(PCP_INC_DIR) may not be on
 # the default cpp include search path.
-CFLAGS		+= -I$(PCP_INC_DIR)/..
+# Also add -I$(PCP_INC_DIR) for internal headers like libpcp.h
+CFLAGS		+= -I$(PCP_INC_DIR)/.. -I$(PCP_INC_DIR)
 else
 CFLAGS		+= -I../../src
 endif