env: move extern environment[] to environment.h

Extract all extern declarations for environment out of c files
into the environment.h header.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
diff --git a/tools/envcrc.c b/tools/envcrc.c
index feebbab..111d9f6 100644
--- a/tools/envcrc.c
+++ b/tools/envcrc.c
@@ -61,6 +61,7 @@
 #endif	/* CONFIG_ENV_IS_IN_FLASH */
 
 #if defined(ENV_IS_EMBEDDED) && !defined(CONFIG_BUILD_ENVCRC)
+# include <environment.h>
 # define CONFIG_BUILD_ENVCRC 1
 #endif
 
@@ -77,7 +78,7 @@
 
 #ifdef CONFIG_BUILD_ENVCRC
 extern unsigned int env_size;
-extern unsigned char environment;
+extern env_t environment;
 #endif	/* CONFIG_BUILD_ENVCRC */
 
 int main (int argc, char **argv)
@@ -85,7 +86,7 @@
 #ifdef CONFIG_BUILD_ENVCRC
 	unsigned char pad = 0x00;
 	uint32_t crc;
-	unsigned char *envptr = &environment,
+	unsigned char *envptr = (unsigned char *)&environment,
 		*dataptr = envptr + ENV_HEADER_SIZE;
 	unsigned int datasize = ENV_SIZE;
 	unsigned int eoe;