Reset struct alignment back to standard after each #pragma pack (n)

When using #pragma pack (n) to change the alignment for a struct
to n bytes, it is necessary to reset the alignment to the standard
value as otherwise the changed alignment is used throughout the
whole program code which causes other structs to become unaligned.

basicmbr.h

@@ -34,6 +34,7 @@ struct TempMBR {
    struct MBRRecord partitions[4];
    uint16_t MBRSignature;
 }; // struct TempMBR
+#pragma pack ()
 
 // Possible states of the MBR
 enum MBRValidity {invalid, gpt, hybrid, mbr};

bsd.h

@@ -89,5 +89,6 @@ class BSDData {
       int GetNumParts(void);
       GPTPart AsGPT(int i); // Return BSD part. as GPT part.
 }; // struct MBRData
+#pragma pack ()
 
 #endif

gpt.h

@@ -57,6 +57,7 @@ struct GPTHeader {
    uint32_t partitionEntriesCRC;
    unsigned char reserved2[GPT_RESERVED];
 }; // struct GPTHeader
+#pragma pack ()
 
 // Data in GPT format
 class GPTData {

mbrpart.h

@@ -50,6 +50,7 @@ struct MBRRecord {
    uint32_t firstLBA; // see above
    uint32_t lengthLBA;
 }; // struct MBRRecord
+#pragma pack ()
 
 class MBRPart {
 protected: