`cat`/file.h: move `concatFileToStdout` func to file.h.

another thing i figure may be somewhat needed.

lib/file.h

@@ -1,4 +1,6 @@
 #include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
 
 /*
 BSD 3-Clause License
@@ -49,3 +51,18 @@ static _Bool isSymlink(const char *path) {
   lstat(path, &path_stat);
   return S_ISLNK(path_stat.st_mode);
 }
+
+static int concatFileToStdout(char *file) {
+  FILE *fp;
+  fp = fopen(file, "r");
+  if (fp == NULL) {
+    printf("failed to open '%s'. perhaps the path doesn't exist?\n", file);
+    exit(1);
+  }
+  char *contents = malloc(2);
+  while (fgets(contents, 2, fp) != NULL) {
+  	printf("%s", contents);
+  }
+  free(contents);
+  return 0;
+}

src/cat.c

@@ -4,6 +4,8 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "file.h"
+
 /*
 BSD 3-Clause License
 
@@ -36,21 +38,6 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
-int concatFileToStdout(char *file) {
-  FILE *fp;
-  fp = fopen(file, "r");
-  if (fp == NULL) {
-    printf("failed to open '%s'. perhaps the path doesn't exist?\n", file);
-    exit(1);
-  }
-  char *contents = malloc(LINE_MAX + 1);
-  while (fgets(contents, LINE_MAX + 1, fp) != NULL) {
-    printf("%s", contents);
-  }
-  free(contents);
-  return 0;
-}
-
 int main(int argc, char **argv) {
   if (argc == 1) {
     char ch;