Fix compiler warnings

Addressing:
sce_engine.c: In function ‘sce_check_result_export’:
sce_engine.c:204:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if (ret < strlen(v->std_out))
          ^
sce_engine.c:205:3: warning: implicit declaration of function ‘dE’ [-Wimplicit-function-declaration]
   dE("Failed to write stdout result to %s.\n", target_file);
   ^~
sce_engine.c:209:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if (ret < strlen(v->std_err))
          ^

src/SCE/sce_engine.c

@@ -35,6 +35,7 @@
 #include "common/list.h"
 #include "common/oscap_acquire.h"
 #include "common/oscap_string.h"
+#include "common/debug_priv.h"
 #include "sce_engine_api.h"
 
 #include <stdlib.h>
@@ -200,14 +201,14 @@ void sce_check_result_export(struct sce_check_result* v, const char* target_file
 	oscap_string_iterator_free(it);
 	fprintf(f, "\t</sceres:environment>\n");
 	fprintf(f, "\t<sceres:stdout><![CDATA[\n");
-	int ret = fwrite(v->std_out, 1, strlen(v->std_out), f);
+	size_t ret = fwrite(v->std_out, 1, strlen(v->std_out), f);
 	if (ret < strlen(v->std_out))
-		dE("Failed to write stdout result to %s.\n", target_file);
+		oscap_seterr(OSCAP_EFAMILY_SCE, "Failed to write stdout result to %s.\n", target_file);
 	fprintf(f, "\t]]></sceres:stdout>\n");
 	fprintf(f, "\t<sceres:stderr><![CDATA[\n");
 	ret = fwrite(v->std_err, 1, strlen(v->std_err), f);
 	if (ret < strlen(v->std_err))
-		dE("Failed to write stderr result to %s.\n", target_file);
+		oscap_seterr(OSCAP_EFAMILY_SCE, "Failed to write stderr result to %s.\n", target_file);
 	fprintf(f, "\t]]></sceres:stderr>\n");
 	fprintf(f, "\t<sceres:exit_code>%i</sceres:exit_code>\n", sce_check_result_get_exit_code(v));
 	fprintf(f, "\t<sceres:result>%s</sceres:result>\n", xccdf_test_result_type_get_text(sce_check_result_get_xccdf_result(v)));