make gcc shut up

If -flto is used then gcc will generate a lot more warnings than before,
among them a number of use-without-initialization warnings. Most of them
without are false positives, but let's make them go away, because it
doesn't really matter.

src/shared/acpi-fpdt.c

@@ -83,7 +83,7 @@ struct acpi_fpdt_boot {
 int acpi_get_boot_usec(usec_t *loader_start, usec_t *loader_exit) {
         _cleanup_free_ char *buf = NULL;
         struct acpi_table_header *tbl;
-        size_t l;
+        size_t l = 0;
         struct acpi_fpdt_header *rec;
         int r;
         uint64_t ptr = 0;

src/shared/boot-timestamps.c

@@ -26,7 +26,7 @@
 #include "efivars.h"
 
 int boot_timestamps(const dual_timestamp *n, dual_timestamp *firmware, dual_timestamp *loader) {
-        usec_t x, y, a;
+        usec_t x = 0, y = 0, a;
         int r;
         dual_timestamp _n;
 

src/shared/efivars.c

@@ -130,7 +130,7 @@ int efi_get_variable(
 
 int efi_get_variable_string(sd_id128_t vendor, const char *name, char **p) {
         _cleanup_free_ void *s = NULL;
-        size_t ss;
+        size_t ss = 0;
         int r;
         char *x;
 
@@ -393,7 +393,7 @@ fail:
 static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) {
         _cleanup_free_ char *j = NULL;
         int r;
-        uint64_t x;
+        uint64_t x = 0;
 
         assert(name);
         assert(u);

src/shared/sleep-config.c

@@ -220,8 +220,8 @@ static int hibernation_partition_size(size_t *size, size_t *used) {
 
 static bool enough_memory_for_hibernation(void) {
         _cleanup_free_ char *active = NULL;
-        unsigned long long act;
-        size_t size, used;
+        unsigned long long act = 0;
+        size_t size = 0, used = 0;
         int r;
 
         r = hibernation_partition_size(&size, &used);

src/shared/socket-util.c

@@ -585,7 +585,7 @@ int getpeername_pretty(int fd, char **ret) {
                 return -errno;
 
         if (sa.sa.sa_family == AF_UNIX) {
-                struct ucred ucred;
+                struct ucred ucred = {};
 
                 /* UNIX connection sockets are anonymous, so let's use
                  * PID/UID as pretty credentials instead */

src/shared/util.c

@@ -5903,7 +5903,7 @@ int proc_cmdline(char **ret) {
         int r;
 
         if (detect_container(NULL) > 0) {
-                char *buf, *p;
+                char *buf = NULL, *p;
                 size_t sz = 0;
 
                 r = read_full_file("/proc/1/cmdline", &buf, &sz);