C programming error: expected '{' before string constant : <p>Here is the error I am receiving,</p>

<pre><code>drivers/mmc/host/sdhci-msm.c: In function 'sdhci_msm_probe':
drivers/mmc/host/sdhci-msm.c:169:23: error: expected '{' before string constant
 #define HOST_MMC_MMC  "mmc0"
                       ^
drivers/mmc/host/sdhci-msm.c:2818:9: note: in expansion of macro 'HOST_MMC_MMC'
  struct HOST_MMC_MMC;
         ^ 
</code></pre>

<p>This issue is perplexing and I am very new to C so any help is appreciated. </p>
